Image display apparatus and image adjusting method

ABSTRACT

An image display apparatus includes: an image signal processing unit which adjusts an input grayscale values included in an input image signal according to a predetermined grayscale characteristic; a display unit which displays an image based on an image signal included in an output grayscale value adjusted by the image signal processing unit; and a grayscale characteristic changing unit which changes a correlation between the input and output grayscale values defined based on the grayscale characteristic.

This is a Continuation of application Ser. No. 11/462,172 filed Aug. 3,2006. This application claims the benefit of Japanese Patent ApplicationNos. 2005-231700 2005-231701, and 2005-231702, in which all were filedon Aug. 10, 2005. The disclosure of the prior applications is herebyincorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to an image display apparatus fordisplaying an image represented by an image signal and an imageadjusting method for the image display apparatus.

2. Related Art

In the related art, an image display apparatus capable of adjusting animage represented by an image signal according to contents of the imageor projection environment has been proposed. For example, in a projectordisclosed in JP-A-2005-99620, three types of selection items “dynamic”,“natural”, and “soft” are provided, and γ values corresponding to theadjusting items are stored. The projector sets the γ value according toselected adjusting items and performs grayscale adjusting (hereinafter,referred to a “γ correction”) on the image signal.

In the related art, when the image adjusting is performed by an imagedisplay apparatus, a small number of predetermined selection items areselected, so that the adjusting is not smoothly performed.

If the number of adjusting items may be increased in order to implementthe smooth image adjusting, a change of the image involved with theimage adjusting is not easy to perceive in advance. In addition, it isdifficult to determine which adjusting items are selected to performdesired image adjusting.

SUMMARY

An advantage of some aspects of the invention is to provide an imagedisplay apparatus capable of easily performing smooth image adjustingaccording to user's preferences and an image adjusting method for theimage display apparatus.

According to an aspect of the invention, there is provided an imagedisplay apparatus comprising: an image signal processing unit whichadjusts an input grayscale values included in an input image signalaccording to a predetermined grayscale characteristic; a display unitwhich displays an image based on an image signal included in an outputgrayscale value adjusted by the image signal processing unit; and agrayscale characteristic changing unit which changes a correlationbetween the input and output grayscale values defined based on thegrayscale characteristic.

According to such a construction, since the grayscale characteristicchanging unit which changes the grayscale characteristic for adjustingthe image signal, that is, the correlation between the input and outputgrayscale values is provided, it is possible to smoothly perform theimage adjusting according to user's preferences by changing thecorrelation.

The image display apparatus may further comprise an OSD unit whichdisplays a selection screen used to decide a to-be-used grayscalecharacteristic among a plurality of the grayscale characteristicsincluding a custom characteristic capable of changing the correlation soas to overlap the image; and a manipulator which receives a selectionmanipulation of selecting one of a plurality of the grayscalecharacteristics and a decision manipulation of deciding the grayscalecharacteristic selected by the selection manipulation in a state thatthe selection screen is displayed, wherein the image signal processingunit adjusts the image signal according to the grayscale characteristicfinally decided by the decision manipulation and adjusts the imagesignal according the grayscale characteristic selected when theselection manipulation is performed in a state that the selection screenis overlapped.

According to such a construction, in a step where the selectionmanipulation for selecting one of a plurality of the grayscalecharacteristics is performed, the adjusting according to the selectedgrayscale characteristic is performed on the image signal, so that it ispossible to select the to-be-used grayscale characteristic while theadjusted image is identified. Namely, it is possible to easily selectthe to-be-used grayscale characteristic.

In the aforementioned image display apparatus, the grayscalecharacteristic changing unit may include: an OSD unit which displays aselection cursor used to select a desired image portion of the image, acharacteristic identification screen including a graph representing thecorrelation, and a grayscale adjusting screen used to change thecorrelation so as to overlap the image; and a manipulator which is usedto perform a starting manipulation of starting the changing of thecorrelation, an image selection manipulation of selecting the imageportion by using the selection cursor, and an image decisionmanipulation of deciding the image portion selected by the imageselection manipulation, wherein, when the starting manipulation isperformed, the image is overlapped with the selection cursor, wherein,when the image selection manipulation is performed, the characteristicidentification screen is overlapped with the image signal, and anadjusting point corresponding to the grayscale value of the selectedimage portion is distinctively represented on the graph, and wherein,when the image decision manipulation is performed, the grayscaleadjusting screen used to change the correlation at the adjusting pointis overlapped with the image.

According to such a construction, in the grayscale characteristicchanging unit, when the image selection manipulation of selecting theimage portion is performed, the adjusting point corresponding to thegrayscale value of the selected image portion is distinctivelydisplayed, and when the image decision manipulation of deciding theselected image portion is performed, the grayscale adjusting screen usedto change the correlation at the adjusting point is displayed.Therefore, the adjusting point where the correlation is to be changedcan be selected from the image, so that it is possible to easily performdesired image adjusting. In addition, in order to distinctivelyrepresent the adjusting point, the adjusting point may be blinked anddisplayed with a color tone different from other adjusting points.

In the aforementioned image display apparatus, the grayscalecharacteristic changing unit may include: an OSD unit which displays aselection cursor used to select a desired image portion of the image onthe image; and a manipulator which is used to performs a startingmanipulation of starting the changing of the correlation and an imageselection manipulation of selecting the image portion by using theselection cursor, wherein, when the starting manipulation is performed,the image is overlapped with the selection cursor, and wherein, when theimage selection manipulation is performed, an image portion having agrayscale value substantially equal to that of the selected imageportion is blinked, and the grayscale adjusting screen is overlappedwith the image so as to change the correlation in the blinked imageportion.

According to such a construction, when the image selection manipulationof selecting the image portion is performed, the grayscalecharacteristic changing unit blinks the image portion having a grayscalesubstantially equal to that of the selected image portion, so thatportions of which correlation is to changed can be easily visuallyperceived.

According to another aspect of the invention, there is provided an imagedisplay apparatus for displaying an image represented by an image signalon a display unit, comprising: a storage unit which stores a pluralityof grayscale characteristics including a custom characteristic capableof customizing a characteristic used to adjust a grayscalecharacteristic in the image signal; an OSD unit which overlaps aselection screen used to select one of a plurality of the grayscalecharacteristics with the image signal; a manipulator which is used toperform at least a manipulation of selecting one of the grayscalecharacteristics from the selection screen and a manipulation of decidingselection contents; and an image signal processing unit which performsan image process including adjusting of the grayscale characteristic onthe image signal, wherein, where a manipulation of selecting thegrayscale characteristic on the selection screen is performed by usingthe manipulator, the image signal processing unit adjusts the grayscalecharacteristic of the image signal based on the selected grayscalecharacteristic and displays an image on the display unit based on theimage signal subjected to the adjusting.

According to such a construction, the storage unit stores a plurality ofthe grayscale characteristics including the custom characteristic whichcan customize the characteristic used for the image adjusting.Therefore, the image display apparatus has a large number of selectionitems of the grayscale characteristic, and the selection items can be inaccordance with the user's preferences.

When the manipulation of selecting the grayscale characteristic in theselection screen is performed in the manipulator, the image signalprocessing unit adjusts the grayscale characteristic of the image signalbased on the selected grayscale characteristic and displays the image onthe display unit based on the image signal subjected to the adjusting.Therefore, in a step of selecting the adjusted contents, it is possibleto identify the image including the adjusted contents in a background ofthe selection screen.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting can be performed according to theuser's preferences, so that it is possible to identify the imageincluding the adjusted contents in the step of selecting the adjustedcontents.

In the aforementioned image display apparatus, the selection screen mayinclude a graph representing a correlation between input and outputgrayscale levels of the selected grayscale characteristic.

According to such a construction, the selection screen may include agraph representing a correlation between input and output grayscalelevels of the selected grayscale characteristic, so that the graphrepresenting the selected grayscale characteristic can be visuallyperceived.

Accordingly, in the image display apparatus according to the aspect ofthe invention, in the step of selecting the adjusted contents, it ispossible to identify the graph representing the grayscale characteristicof the image as well as the image including the adjusted contents.

In the aforementioned image display apparatus, when a manipulation ofselecting the custom characteristic of the selection screen and decidingselection contents by using the manipulator is performed, the imagesignal processing unit may perform an image process on the image signalbased on a grayscale characteristic included in the customcharacteristic, wherein the OSD unit stops the overlapping of theselection screen and overlaps a graph adjusting screen including a graphrepresenting a grayscale characteristic at an initial setting of thecustom characteristic with the image signal, and wherein the graphadjusting screen includes a plurality of dot displayed portions whichrepresent output grayscale levels at a plurality of adjusting pointsdisposed according to input grayscale levels and are used to adjust thegrayscale characteristic.

According to such a construction, when the custom characteristic isselected and decided, the graph adjusting screen including the graphrepresenting the grayscale characteristic at the initial setting of thecustom characteristic is displayed, and the graph adjusting screenincludes a plurality of the dot displayed portions which represent theoutput grayscale levels at a plurality of the adjusting point disposedaccording to the input grayscale levels and are used to adjust thegrayscale characteristic. Therefore, due to the graph adjusting screen,it is possible to perform the adjusting of the grayscale characteristicwhile the grayscale characteristic at the initial setting of the customcharacteristic is identified.

Accordingly, in the image display apparatus according to the aspect ofthe invention, it is possible to perform the image adjusting accordingto the user's preferences while the grayscale characteristic isidentified by using the graph.

In the aforementioned image display apparatus, when a manipulation ofselecting the custom characteristic of the selection screen and decidingselection contents by using the manipulator is performed, the OSD unitmay stop the overlapping of the selection screen and overlap acharacteristic identification screen which is a graph representing agrayscale characteristic at an initial setting of the customcharacteristic with the image signal, wherein the image signalprocessing unit performs an image process on the image signal based on agrayscale characteristic included in the custom characteristic, andwherein, when a manipulation of selecting one of a plurality of dotdisplayed portions representing output grayscale levels at the adjustingpoints in the graph is performed by using the manipulator, the OSD unitstops the overlapping of the characteristic identification screen andoverlaps a grayscale adjusting screen which is smaller than the imageand used to adjust the output grayscale level at the selected adjustingpoint with the image signal.

According to such a construction, when the custom characteristic isselected and decided, the characteristic identification screen which isthe graph representing the grayscale characteristic at the initialsetting of the custom characteristic is displayed. Therefore, due to thecharacteristic identification screen, it is possible to identify thegrayscale characteristic at the initial setting of the customcharacteristic.

In addition, when a manipulation of selecting one of a plurality of dotdisplayed portions representing output grayscale levels at the adjustingpoints in the graph of the characteristic identification screen isperformed, the OSD unit stops the overlapping of the characteristicidentification screen and overlaps the grayscale adjusting screen whichis smaller than the image of the characteristic identification used toadjust the output grayscale level at the selected adjusting point withthe image signal. Therefore, due to the grayscale adjusting screen, itis possible to perform the adjusting of the output grayscale level atthe selected adjusting point.

Accordingly, in the image display apparatus according to the aspect ofthe invention, it is possible to perform the image adjusting accordingto the user's preferences after the grayscale characteristic isidentified by using the graph.

In the aforementioned image display apparatus, when a manipulation ofselecting the custom characteristic of the selection screen and decidingselection contents by using the manipulator is performed, the OSD unitmay stop the overlapping of the selection screen and overlap a selectioncursor which is used to select a desired image portion on the image withthe image signal, wherein the image signal processing unit stops animage which is subjected to an image process based on a grayscalecharacteristic included in the custom characteristic, and wherein, whena manipulation of selecting the image portion is performed by using theselection cursor, the OSD unit overlaps a graph adjusting screenrepresenting output grayscale levels at a plurality of adjusting pointsdisposed according to input grayscale levels used to adjust thegrayscale characteristic and including a plurality of dot displayedportions capable of adjusting the output grayscale level with the imagesignal.

According to such a construction, by using the selection and decision ofthe custom characteristic as a trigger, the selection cursor isdisplayed, and the image is stopped. Therefore, although the movingimage is not easy to select, the selection of the image portion by usingthe selection cursor can be easily performed on the still image.

In addition, when a manipulation of selecting the image portion isperformed by using the selection cursor, the OSD unit overlaps a graphadjusting screen representing output grayscale levels at a plurality ofadjusting points disposed according to input grayscale levels used toadjust the grayscale characteristic and including a plurality of dotdisplayed portions capable of adjusting the output grayscale level withthe image signal. Therefore, due to the graph adjusting screen, it ispossible to perform the adjusting of the grayscale characteristic whilethe grayscale characteristic is identified.

Accordingly, in the image display apparatus according to the aspect ofthe invention, a desired image portion can be easily selected, so thatit is possible to perform the image adjusting according to the user'spreferences while the grayscale characteristic is defined confirmed byusing the graph.

In the aforementioned image display apparatus, when a manipulation ofselecting the custom characteristic of the selection screen and decidingselection contents by using the manipulator is performed, the OSD unitmay stop the overlapping of the selection screen and overlap a selectioncursor used to select a desired image portion on the image with theimage signal, wherein the image signal processing unit stops an imagewhich is subjected to an image process based on a grayscalecharacteristic included in the custom characteristic, and wherein, whena manipulation of selecting the image portion is performed by using theselection cursor, the OSD unit overlaps a grayscale adjusting screenused to adjust an output grayscale level at an adjusting point of thegrayscale characteristic corresponding g to the selected image portionwith the image signal.

According to such a construction, by using the selection and decision ofthe custom characteristic as a trigger, the selection cursor isdisplayed, and the image is stopped. Therefore, although the movingimage is not easy to select, the selection of the image portion by usingthe selection cursor can be easily performed on the still image.

In addition, when a manipulation of selecting the image portion isperformed by using the selection cursor, the OSD unit overlaps thegrayscale adjusting screen used to adjust the output grayscale level atthe adjusting point of the grayscale characteristic corresponding to theselected image portion with the image signal. Therefore, due to thegrayscale adjusting screen, it is possible to perform the adjusting ofthe output grayscale level at the selected adjusting point.

Accordingly, in the image display apparatus according to the aspect ofthe invention, a desired image portion can be easily selected, so thatit is possible to perform the image adjusting according to the user'spreferences.

In the aforementioned image display apparatus, when an adjustingmanipulation of adjusting a grayscale level in the graph adjustingscreen or the grayscale adjusting screen is performed, the image signalprocessing unit may sequentially adjust a grayscale value of an imageportion corresponding to the adjusting point in the image according tothe output grayscale level which is subjected to the adjustingmanipulation.

According to such a construction, when an adjusting manipulation ofadjusting a grayscale level in the graph adjusting screen or thegrayscale adjusting screen is performed, the image signal processingunit sequentially adjusts a grayscale value of an image portioncorresponding to the adjusting point in the image according to theoutput grayscale level which is subjected to the adjusting manipulation.Therefore, in the step of performing the adjusting, it is possible toidentify the image including the adjusted contents in real-time.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting can be performed according to theuser's preferences, in the step of performing the adjusting, it ispossible to identify the image including the adjusted contents inreal-time.

In the aforementioned image display apparatus, when a manipulation ofselecting the custom characteristic of the selection screen and decidingselection contents by using the manipulator is performed, before a graphadjusting mode which uses a graph and starts from the graph adjustingscreen and the characteristic identification screen or a cursoradjusting mode which starts from the selection cursors proceeds, the OSDunit may stop the overlapping of the selection screen and overlap abranch screen used to select one of the graph adjusting mode and thecursor adjusting mode with the image signal.

According to such a construction, by using the selection and decision ofthe custom characteristic as a trigger, the OSD unit overlaps the branchscreen used to select one of the graph adjusting mode and the cursoradjusting mode with the image signal. Therefore, due to the branchscreen, it is possible to select one of the graph adjusting mode and thecursor adjusting mode.

Accordingly, in the image display apparatus according to the aspect ofthe invention, it is possible to select the adjusting method accordingto the user's preferences.

In the aforementioned image display apparatus, a selection record thatthe graph selected in the branch screen or the cursor image adjustingmode is selected may be stored in the storage unit, and when amanipulation of selecting the custom characteristic of the selectionscreen is performed by using the manipulator, the OSD unit overlaps thebranch screen with the image signal in a state that an image adjustingmode in the selection record stored in the storage unit is selected.

According to such a construction, a selection record is stored in thestorage unit, and when a manipulation of selecting the customcharacteristic of the selection screen is performed by using themanipulator, the OSD unit overlaps the branch screen with the imagesignal in a state that an image adjusting mode in the selection recordstored in the storage unit is selected. The branch screen is displayedin a state that the branch screen includes user's selection records.Therefore, a probability that the user performs the selectionmanipulation for the adjusting mode is reduced.

Accordingly, the image display apparatus according to the aspect of theinvention can be conveniently used.

In the aforementioned image display apparatus, a size of each ofmanipulation screens including the selection screen, the graph adjustingscreen, the characteristic identification screen, the grayscaleadjusting screen, and the branch screen may be ¼ or less of the image.

According to such a construction, the size of each of manipulationscreens including the selection screen, the graph adjusting screen, thecharacteristic identification screen, the grayscale adjusting screen,and the branch screen is ¼ or less of the image. Therefore, although thearea covered by the manipulation screen is excluded, the image having ¾or more of the entire area can be identified.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting can be performed while the imagestate is identified.

In the aforementioned image display apparatus, each of manipulationscreens including the graph adjusting screen, the characteristicidentification screen, the grayscale adjusting screen, and the branchscreen may be disposed in an inner side of one of four corners of theimage having a substantially rectangular shape as an initial setting,wherein the OSD unit moves the position of the manipulation screenwithin an range of the image so as not to overlap the selected imageportion.

According to such a construction, each of the manipulation screens isdisposed in an inner side of one of four corners of the image having asubstantially rectangular shape as an initial setting. Therefore, thecentral portion of the image is not covered by the manipulation screens.

In addition, the OSD unit moves the position of the manipulation screenin an inner region of the image so that the selected image portioncannot be overlapped with the manipulation screen. Therefore, theadjusting state of the selected image portion which needs to be mostcarefully adjusted can be identified at the time of the adjusting.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting can be performed while the imagestate is always identified.

In the aforementioned image display apparatus, a grayscalecharacteristic in a default initial setting of the custom characteristicmay be changed, and the grayscale characteristic may be set to onegrayscale characteristic among a plurality of the grayscalecharacteristics including a linear grayscale characteristic stored inthe storage unit.

According to such a construction, the grayscale characteristic in thedefault initial setting of the custom characteristic can be changed andis set to one grayscale characteristic among a plurality of thegrayscale characteristics including a linear grayscale characteristicstored in the storage unit. Therefore, the grayscale characteristicaccording to the user's preferences can be selected as a referencecharacteristic.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting according to the user's preferencescan be performed.

In the aforementioned image display apparatus, the custom characteristicadjusted in the graph adjusting screen or the grayscale adjusting screenis stored in the storage unit and displayed as one of the selectionitems of a plurality of the grayscale characteristics when the selectionscreen is displayed.

According to such a construction, the adjusted custom characteristic isstored in the storage unit and displayed as one of the selection itemsof a plurality of the grayscale characteristics when the selectionscreen is displayed. Therefore, the adjusted custom characteristics arestored, so that it can be easily reproduced.

Accordingly, the image display apparatus according to the aspect of theinvention can be conveniently used.

In the aforementioned image display apparatus, the image displayapparatus is a projector including: a light source unit which supplieslight; an optical modulation device which modulates light emitted fromthe light source unit into a modulated light representing an imagedefined by the image signal; and a projection lens which magnifies andprojects the modulated light.

The projector projects the image on the screen, that is, the projectionplane to display the image. Therefore, the projected image needs to beadjusted so as to be suitable for projection environment according tobrightness of the projection environment, a color tone of the installedscreen, or the like. For this reason, a high-performance image adjustingmethod of performing the image adjusting frequently is required.

According to such a construction, the image display apparatus is aprojector which modulates light emitted from the light source unit intoa modulated light representing an image defined by an image signal byusing an optical modulation device and magnifies and projects themodulated light by using the projection lens. Therefore, the projectedimage on a large-sized screen can be subjected to the image adjusting soas to be suitable for the projection environment based on a plurality ofthe grayscale characteristics including the custom characteristic whichcan be customized.

Accordingly, the image display apparatus according to the aspect of theinvention is suitable for a projector.

According to still another aspect of the invention, there is provided animage display apparatus for displaying an image represented by an imagesignal on a display unit, comprising: an OSD unit which overlaps aselection cursor used to select a desired image portion of the image, acharacteristic identification screen including a graph representing acorrelation between input and output grayscale levels of a grayscalecharacteristic at an initial setting of the image, and a grayscaleadjusting screen used to adjust grayscales of a plurality of adjustingpoints in the grayscale characteristic of the image with the imagesignal; a manipulator which is used to perform at least a manipulationof starting adjusting of the grayscale characteristic of the image, aselection manipulation of selecting the image portion by using theselection cursor, and a manipulation of deciding the selected imageportion; and an image signal processing unit which stops the image andallows the OSD unit to display the selection cursor on the display unitwhen image adjusting including the grayscale characteristic adjusting isperformed on the image signal and a manipulation of performing the imageadjusting is performed by using the manipulator, wherein, when amanipulation of selecting the image portion by using the selectioncursor is performed in the manipulator, the OSD unit overlaps thecharacteristic identification screen where the adjusting pointcorresponding to a grayscale of the selected image portion is blinked ora color tone of the adjusting point is changed with the image signal,and wherein, when a manipulation of deciding the selected image portionis performed in the manipulator, the OSD unit overlaps the grayscaleadjusting screen of the adjusting point corresponding to the grayscaleof the selected image portion with the image signal.

According to such a construction, when the manipulation for the imageadjusting is performed, the image signal processing unit stops the imageand displays the selection cursor for selecting the desired imageportion on the image. Even in case of a moving image where the imageportion is not easy to selection due to a change of the image, since theimage is stopped, so that the image portion can be easily selected. Inaddition, the desired image portion can be selected from the still imageby using the selection cursor.

When the manipulation of selecting the image portion by using theselection cursor is performed in the manipulator, the OSD unit blinksthe adjusting point corresponding to the grayscale of the selected imageportion or overlaps the characteristic identification screen where thecolor tone of the adjusting point is changed with the image signal. Theposition of the image portion in the grayscale characteristic of theentire image is distinctively represented on the graph. Accordingly, theadjusting point in the grayscale characteristic of the entire image canbe identified by using the graph before the grayscale adjusting isperformed.

In addition, when the manipulation of deciding the selected imageportion is performed by using the manipulator, the OSD unit overlaps thegrayscale adjusting screen at the adjusting point corresponding to thegrayscale of the selected image portion with the image signal.Therefore, due to the grayscale adjusting screen, the grayscaleadjusting of the selected image portion can be performed.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the desired adjusting portion can be selected from thedisplayed image, and the image adjusting for the selected adjustingportion can be performed after the grayscale characteristic of theentire image is identified.

In the aforementioned image display apparatus, the image signalprocessing unit may comprise: a gamma correcting unit which corrects oneof a plurality of reference grayscale characteristics defined in advanceso that a grayscale characteristic unique to the display unit issuitable for at least installation environment; and a grayscale pointadjusting unit which adjusts output grayscale values at a plurality ofadjusting points disposed according to input levels in the referencegrayscale characteristic, wherein grayscale adjusting for the imagesignal in the image signal processing unit is performed based on agrayscale characteristic obtained by combining grayscale correction inthe gamma correcting unit and grayscale adjusting in the grayscale pointadjusting unit, and wherein, when adjusting for the output grayscalevalue in the grayscale adjusting screen for the selected adjusting pointis performed, the grayscale point adjusting unit changes the outputgrayscale value of the adjusting point according to adjusted contents.

The image signal processing unit comprises: a gamma correcting unitwhich corrects one of a plurality of reference grayscale characteristicsdefined in advance so that a grayscale characteristic unique to thedisplay unit is suitable for at least installation environment; and agrayscale point adjusting unit which adjusts output grayscale values ata plurality of adjusting points disposed according to input levels inthe reference grayscale characteristic. The functions are performed byindividual dedicated units. Therefore, since the dedicated constructionscan be formed, it is possible to simplify the constructions.

In addition, the grayscale adjusting to the image signal in the imagesignal processing unit is performed by using the grayscalecharacteristic obtained by combining the grayscale correction in thegamma correcting unit and the grayscale adjusting in the grayscale pointadjusting unit. Therefore, due to the two adjusting portions, ahighly-accurate grayscale adjusting can be performed.

When the adjusting of the output grayscale value in the grayscaleadjusting screen of the selected adjusting point is performed, thegrayscale point adjusting unit changes the output grayscale value of theadjusting point according to the adjusted contents. Therefore, the imageon the background of the grayscale adjusting screen can be updated by animage including the adjusted contents in real-time.

Accordingly, in the image display apparatus according to the aspect ofthe invention, since the highly-accurate grayscale adjusting can beperformed by using a simple grayscale adjusting construction, the imageincluding the adjusted contents can be identified in real-time.

In the aforementioned image display apparatus, the selection cursorincludes a pixel selection portion having a size capable of selectingthree or more plural consecutive pixels among the pixels in thedisplayed unit, and wherein the adjusting point of the grayscalecharacteristic corresponding to the selected image portion is obtainedby selecting an adjusting point having an input grayscale level closestto an average value of grayscale values of a plurality of the pixelsselected by the pixel selection portion or an average value excludingmaximum and minimum values from the grayscale values of a plurality ofthe pixels selected by the pixel selection portion.

According to such a construction, the selection cursor includes thepixel selection portion which has a size capable of selecting three ormore plural consecutive pixels among the pixels in the display unit.Therefore, the selected portion according to the user's intention can bedetermined based on the pixel data in a plurality of the pixels having awidth.

In addition, with respect to the adjusting point of the grayscalecharacteristic corresponding to the selected image portion, theadjusting point having the input grayscale level closest to the averagevalue of the grayscale values for a plurality of the pixels selected bythe pixel selection portion or the average value excluding the maximumand minimum grayscale values from the grayscale values for a pluralityof the pixels selected by the pixel selection portion is selected.Therefore, since the influence of the pixel data including the noise canbe reduced, the adjusting point corresponding to the image portionaccording to the user's intention can be selected.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the adjusting portion according to the user's intentioncan be accurately selected from the projected image.

In the aforementioned image display apparatus, the pixel selectionportion has a size capable of selecting a total of nine pixels in asquare shape where three consecutive pixels are arrayed in each ofvertical and horizontal directions.

According to such a construction, the pixel selection portion has a sizecapable of selecting a total of nine pixels in a square shape where thethree consecutive pixels are arrayed in each of the vertical andhorizontal directions. Therefore, although the average value is obtainedfrom the grayscale values excluding the pixels having the maximum andminimum grayscale values, the effective pixel data for the seven pixelscan be obtained. In addition, since the pixel selection portion has asuitable size over the entire image, it can be easily visuallyperceived. In addition, since the pixel selection portion has a squareshape, the image portion can be easily selected.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the adjusting portion according to the user's intentioncan be easily and accurately selected from the projected image.

In the aforementioned image display apparatus, the selection cursorfurther includes an annular portion which is disposed along acircumference of the pixel selection portion to have a shape which isone-step larger than an outer portion of the pixel selection portion,wherein a relative position of the annular portion to the pixelselection portion is always maintained constant, and the annular potiontogether with the pixel selection portion is moved on the still image.

According to such a construction, the selection cursor further includesthe annular portion which is disposed along the circumference of thepixel selection portion to have a shape which is one-step larger than anouter portion of the pixel selection portion. In addition, a relativeposition of the annular portion to the pixel selection portion is alwaysmaintained constant, and the annular potion together with the pixelselection portion is moved on the still image. Therefore, the selectioncursor has a specific shape having the annular portion of which size islarger by one step than that of the pixel selection portion, and a largeselection cursor can be distinctively displayed on the image.

Accordingly, due to the distinctively displayed selection cursor, adesired image portion can be easily selected.

Accordingly, in the image display apparatus according to the aspect ofthe invention, due to the selection cursor distinctively displayed onthe image, a desired image portion can be easily selected.

In the aforementioned image display apparatus, in the selectionmanipulation for the image portion by using the selection cursor, aposition of the pixel selection portion is controlled by the imagesignal processing unit so that the entire portions of the pixelselection portion are not protruded from the still image, and wherein,when the pixel selection portion reaches an edge of the still image, theselection cursor is displayed in a state that a portion of the imagecorresponding to the annular portion protruding from the still image isexcluded.

According to such a construction, the position of the pixel selectionportion is controlled by the image signal processing unit so that theentire portions of the pixel selection portion are not protruded fromthe still image, and when the pixel selection portion reaches the edgeof the still image, the selection cursor is displayed in a state that aportion of the image corresponding to the annular portion protrudingfrom the still image is excluded. Therefore, due to the selectioncursor, the image portion to the edge of the image can be selected fromthe image, and although the edge of the image is selected, the selectioncursor can be visually perceived.

Accordingly, in the image display apparatus according to the aspect ofthe invention, due to the selection cursor, the desired image portioncan be selected from all the effective image regions.

In the aforementioned image display apparatus, a color tone of theselection cursor is set to one of white and black, and wherein the OSDunit adjusts the color tone of the selection cursor based on a colortone having high contrast among a color tone of the image portionselected by the selection cursor and a color tone of one of black andwhite.

According to such a construction, the OSD unit adjusts the color tone ofthe selection cursor based on a color tone having high contrast among acolor tone of the image portion selected by the selection cursor and acolor tone of one of black and white. The color tone of the selectioncursor is adjusted so as to be an easily visually perceived color tone.

Accordingly, due to the distinctively displayed selection cursor, adesired image portion can be easily selected.

Accordingly, in the image display apparatus according to the aspect ofthe invention, due to the selection cursor distinctively displayed onthe image, a desired image portion can be easily selected.

According to further still another aspect of the invention, there isprovided an image display apparatus for displaying an image representedby an image signal on a display unit, comprising: an OSD unit whichdisplays a selection cursor used to select a desired image portion onthe image; a manipulator which is used to perform at least amanipulation of starting adjusting of the grayscale characteristic ofthe image and a selection manipulation of selecting the image portion byusing the selection cursor; and an image signal processing unit whichstops the image and allows the OSD unit to display the selection cursorwhen image adjusting including the grayscale characteristic adjusting isperformed on the image signal and a manipulation of performing the imageadjusting is performed, wherein, when the image portion is selected fromthe still image by the selection cursor, the image signal processingunit blinks the selected image portion and an image portion having agrayscale substantially equal to that of the selected image portion inthe still image.

According to such a construction, when the manipulation for the imageadjusting is performed, the image signal processing unit stops the imageand displays the selection cursor for selecting the desired imageportion on the image on the display unit. Even in case of a moving imagewhere the image portion is not easy to select due to a change of theimage, since the image is stopped, the image portion can be easilyselected. In addition, the desired image portion can be selected fromthe still image by using the selection cursor.

In addition, when the image portion is selected from the still image bythe selection cursor, the image signal processing unit blinks theselected image portion of the still image and the image portion having agrayscale substantially equal to that of the selected image portion.Therefore, these image portions are displayed so as to be distinguishedfrom other image portions. Therefore, the selected image portion can bedistinctively visually perceived. In addition, even in a case whereunexpected portion is selected, the portion can be identified at aglance.

Accordingly, in the image display apparatus according to the aspect ofthe invention, a desired image adjusting portion can be selected fromthe displayed image, so that the selected image portion can bedistinctively visually perceived.

In the aforementioned image display apparatus, the blinking of the imageportion selected by the selection cursor and the image portion having agrayscale substantially equal to that of the selected image portion isperformed by periodically increasing and decreasing the output grayscalevalue at the adjusting point having the input grayscale level closest tothe grayscale value of the selected image portion among a plurality ofthe adjusting points corresponding to the input grayscale level in thegrayscale characteristic of the image signal representing the stillimage.

According to such a construction, the blinking of the image portionselected by the selection cursor and the image portion having agrayscale substantially equal to that of the selected image portion isperformed by periodically increasing and decreasing the output grayscalevalue at the adjusting point having the input grayscale level closest tothe grayscale value of the selected image portion among a plurality ofthe adjusting points corresponding to the input grayscale level in thegrayscale characteristic of the image signal representing the stillimage. Therefore, the selected image portion and the image portionhaving a grayscale substantially equal to that of the selected imageportion can be blinked by using such a simple method of increasing anddecreasing the output grayscale value at the one adjusting point.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the selected image portion and the image portion selectedtogether with the selected image portion can be visually perceived andidentified by using such a simple method.

In the aforementioned image display apparatus, the image signalprocessing unit includes a gamma correcting unit which corrects onereference grayscale characteristic among a plurality of the referencegrayscale characteristics defined in advance in order to match thegrayscale characteristics unique to the display unit with a visualcharacteristic of a human and a grayscale point adjusting unit whichadjusts the output grayscale value for a plurality of the adjustingpoints disposed according to the input levels in the reference grayscalecharacteristic, wherein grayscale adjusting for the image signal in theimage signal processing unit is performed based on a grayscalecharacteristic obtained by combining grayscale correction in the gammacorrecting unit and grayscale adjusting in the grayscale point adjustingunit, and wherein the blinking of the selected image portion selected bythe selection cursor and an image portion having a grayscalesubstantially equal to that of the selected image portion is performedby the grayscale point adjusting unit.

According to such a construction, the image signal processing unitincludes a gamma correcting unit which corrects one reference grayscalecharacteristic among a plurality of the reference grayscalecharacteristics defined in advance in order to match the grayscalecharacteristics unique to the display unit with a visual characteristicof a human and a grayscale point adjusting unit which adjusts the outputgrayscale value for a plurality of the adjusting points disposedaccording to the input levels in the reference grayscale characteristic.The functions are performed by individual dedicated units. Therefore,since the dedicated constructions can be formed, it is possible tosimplify the constructions.

In addition, the blinking of the selected image portion selected by theselection cursor and an image portion having a grayscale substantiallyequal to that of the selected image portion is performed by thegrayscale point adjusting unit. Therefore, the image portion can beblinked without influence to the reference grayscale characteristic.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the selected image portion and the image portion selectedtogether with the selected image portion can be visually perceived andidentified by using such a simple construction.

In the aforementioned image display apparatus, increment and decrementamounts of the output grayscale value which is periodically increasedand decreased at the adjusting point are ±10% or less of the full scaleof the output grayscale value in the grayscale characteristic.

An output grayscale value of a general image display apparatus isdisplayed with 8 to 10 bits, so that 256 to 1024 output grayscale valuesare generated. When a portion of the screen is visualized by theblinking of the image portion, if the blinking level is periodicallyincreased and decreased from the “zero” level to “maximum” levelaccording to the full scale of the output grayscale level, since thecontrast is too high, the image is flickered, so that observer's eyesbecome fatigued. In addition, since the response of the display unitcannot be caught up with, an inharmonious image may be formed.

According to such a construction, the increment and decrement amounts ofthe output grayscale value which is periodically increased and decreasedat the adjusting point are ±10% or less of the full scale of the outputgrayscale value in the grayscale characteristic. Therefore, due to sucha suitable contrast, the image portion can be visually perceived withoutthe fatigue of the observer's eyes. In addition, the response of thedisplay unit can be sufficiently caught up with.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the selected image portion can be distinctively visuallyperceived without unpleasant feeling.

In the aforementioned image display apparatus, a blinking period of theselected image portion selected by the selection cursor and the imageportion having a grayscale substantially equal to that of the selectionimage portion is in a range of from 0.5 Hz to 3 Hz.

In general, with respect to the visual characteristic of a human, it isknown that, if the blinking period exceeds 3 Hz, unpleasant feelingcaused from the flickering of the image is increased.

According to such a construction, the blinking period of the selectedimage portion selected by the selection cursor and the image portionhaving a grayscale substantially equal to that of the selection imageportion is in a range of from 0.5 Hz to 3 Hz. Therefore, unpleasantfeeling caused from the flicker can be prevented, and the image portioncan be distinctively visually perceived.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the selected image portion can be distinctively visuallyperceived without unpleasant feeling.

In the aforementioned image display apparatus, the OSD unit may overlapa graph adjusting screen including a graph representing a grayscalecharacteristic of the image and smaller than the image with the imagesignal and blink a dot displayed portion corresponding to the selectedimage portion among a plurality of the dot displayed portionsrepresenting output grayscale levels at a plurality of adjusting pointsdisposed according to input grayscale levels used to adjust thegrayscale characteristic in the graph adjusting screen or change a colortone of the dot displayed portion.

According to such a construction, the OSD unit overlaps the graphadjusting screen with the image signal and blinks the dot displayedportion corresponding to the selected image portion among a plurality ofthe dot displayed portions representing output grayscale levels at aplurality of adjusting points disposed according to input grayscalelevels used to adjust the grayscale characteristic in the graphadjusting screen or changes a color tone of the dot displayed portion.Therefore, a current grayscale characteristic can be visually perceivedby using the graph, and a selected portion of the graph can bedistinctively understood.

Accordingly, in the image display apparatus according to the aspect ofthe invention, a current grayscale characteristic can be visuallyperceived by using the graph, and a selected portion of the graph can bedistinctively understood.

In the aforementioned image display apparatus, the OSD unit overlaps acharacteristic identification screen which is a graph representing agrayscale characteristic of the image and smaller than the image withthe image signal and blinks a dot displayed portion corresponding to theselected image portion among a plurality of the dot displayed portionsrepresenting output grayscale levels at a plurality of adjusting pointsdisposed according to input grayscale levels of the grayscalecharacteristic in the characteristic identification screen or changes acolor tone of the dot displayed portion.

According to such a construction, the OSD unit overlaps a characteristicidentification screen which is a graph representing a grayscalecharacteristic of the image and smaller than the image with the imagesignal and blinks a dot displayed portion corresponding to the selectedimage portion among a plurality of the dot displayed portionsrepresenting output grayscale levels at a plurality of adjusting pointsdisposed according to input grayscale levels of the grayscalecharacteristic in the characteristic identification screen or changes acolor tone of the dot displayed portion. Therefore, a current grayscalecharacteristic can be visually perceived by using the graph, and aselected portion of the graph can be distinctively understood.

Accordingly, in the image display apparatus according to the aspect ofthe invention, a current grayscale characteristic can be visuallyperceived by using the graph, and a selected portion of the graph can bedistinctively understood.

In the aforementioned image display apparatus, a blinking period of thedot displayed portion in the graph adjusting screen or thecharacteristic identification screen is in synchronization with ablinking period of the selected image portion selected by the selectioncursor.

According to such a construction, a blinking period of the dot displayedportion in the graph adjusting screen or the characteristicidentification screen is in synchronization with a blinking period ofthe selected image portion selected by the selection cursor. Therefore,it can be visually perceived that the selected image portion and the dotdisplayed portion at the adjusting point corresponding to thecharacteristic identification screen are equal to each other. Inaddition, the periods are synchronized with each other, so that thevisually unpleasant feeling can be prevented.

Accordingly, in the image display apparatus according to the aspect ofthe invention, it can be visually represented that the selected imageportion corresponds to the dot displayed portion.

In the aforementioned image display apparatus, a plurality of theadjusting points are distributed so that a half or more of a totalnumber of the adjusting points are distributed to a range of from a lowgrayscale to an intermediate grayscale in the input grayscale level.

Human eyes are sensitive to a dark color. In addition, the adjusting inthe high grayscale range in the grayscale characteristic may beperformed by “brightness” adjusting, that is, gain adjusting which isprovided to a general image display apparatus.

According to such a construction, a plurality of the adjusting pointsare distributed so that a larger number of the adjusting points aredistributed to a range of from the low grayscale value to theintermediate grayscale value at the input side. Therefore, in the imagedisplay apparatus, a large number of the adjusting points are providedto the grayscale range needed to improve the “image quality” which theuser highly expects in the grayscale adjusting.

Accordingly, in the image display apparatus according to the aspect ofthe invention, the image adjusting according to the user's preferencescan be performed.

In the aforementioned image display apparatus, a predetermined outputgrayscale amount defined for each of the selected adjusting points isdefined as one step, and the graph adjusting screen includes plus andminus buttons used to increase and decrease the grayscale value step bystep, and wherein the predetermined output grayscale amount is set sothat a larger amount is provided to the adjusting points in a lowgrayscale range than the adjusting points in a high grayscale range.

In general, in such image adjusting as grayscale adjusting, thefrequency and amount of adjusting in the high grayscale range are small,but the frequency and amount of adjusting in the low grayscale range arelarge.

According to such a construction, predetermined output grayscale amountsare so set that a larger amount is provided to the adjusting points inthe low grayscale range than the adjusting points in the high grayscalerange. The adjusting amount per one step in the graph adjusting screenis set to the adjusting amounts satisfying the needed usage.

Accordingly, the image display apparatus according to the aspect of theinvention can be conveniently used.

In the aforementioned image display apparatus, when a manipulation ofdeciding the adjusting point selected in the characteristicidentification screen by using the manipulator is performed, the OSDunit stops the overlapping of the characteristic identification screenand overlaps a grayscale adjusting screen used to adjust an outputgrayscale level of the selected adjusting point with the image signal,wherein a predetermined output grayscale amount defined for each of theselected adjusting points is defined as one step, and the grayscaleadjusting screen includes plus and minus buttons used to increase anddecrease the grayscale value step by step, and wherein the predeterminedoutput grayscale amount is set so that a larger amount is provided tothe adjusting points in a low grayscale range than the adjusting pointsin a high grayscale range.

According to such a construction, predetermined output grayscale amountsare so set that a larger amount is provided to the adjusting points inthe low grayscale range than the adjusting points in the high grayscalerange. The adjusting amount per one step in the grayscale adjustingscreen is set to the adjusting amounts satisfying the needed usage.

Accordingly, the image display apparatus according to the aspect of theinvention can be conveniently used.

According to further still another aspect of the invention, there isprovided an image adjusting method for an image display apparatusincluding a display unit which displays an image represented by an imagesignal, a storage unit which stores a plurality of grayscalecharacteristics used to adjust a grayscale characteristic in the imagesignal, an OSD unit which overlaps a selection screen which is used toselect one of a plurality of the grayscale characteristics and smallerthan the image with the image signal, a manipulator which is used toperform at least a manipulation of selecting one of the grayscalecharacteristics from the selection screen and a manipulation of decidingselection contents, and an image signal processing unit which performsan image process including adjusting of the grayscale characteristic onthe image signal, the image adjusting method comprising: when amanipulation of selecting the grayscale characteristic is performed inthe selection screen, adjusting the grayscale characteristic of theimage signal based on the selected grayscale characteristic; displayingthe image on the display unit according to the image signal which issubjected to the adjusting.

The aforementioned image adjusting method comprise: when a manipulationof selecting the grayscale characteristic is performed in the selectionscreen, adjusting the grayscale characteristic of the image signal basedon the selected grayscale characteristic; displaying the image on thedisplay unit according to the image signal which is subjected to theadjusting. Therefore, in a step of selecting the adjusted contents, itis possible to identify the image including the adjusted contents in abackground of the selection screen.

Accordingly, in the image adjusting method for the image displayapparatus according to the aspect of the invention, it is possible toidentify the image including the adjusted contents in the step ofselecting the adjusted contents.

According to further still another aspect of the invention, there isprovided an image adjusting method for an image display apparatusincluding a display unit which displays an image represented by an imagesignal, an OSD unit which overlaps a selection cursor used to select adesired image portion of the image, a characteristic identificationscreen including a graph representing a correlation between input andoutput grayscale levels of a grayscale characteristic at an initialsetting of the image, and a grayscale adjusting screen used to adjustgrayscales of a plurality of adjusting points in the grayscalecharacteristic of the image with the image signal, a manipulator whichis used to perform at least a manipulation of starting adjusting of thegrayscale characteristic of the image, a selection manipulation ofselecting the image portion by using the selection cursor, and amanipulation of deciding the selected image portion, and an image signalprocessing unit which performs an image process including adjusting ofthe grayscale characteristic on the image signal, the image adjustingmethod comprising: when a manipulation of performing the image adjustingis performed, stopping the image and displaying the selection cursor onthe display unit; when a manipulation of selecting the image portion byusing the selection cursor is performed, overlapping the characteristicidentification screen where the adjusting point corresponding to agrayscale of the selected image portion is blinked or a color tone ofthe adjusting point is changed with the image signal; and when amanipulation of deciding the selected image portion is performed,overlapping the grayscale adjusting screen of the adjusting pointcorresponding to a grayscale of the selected image portion with theimage signal.

In the aforementioned image adjusting method, when the manipulation forthe image adjusting is performed, the image is stopped, and theselection cursor is displayed on the image. Even in case of a movingimage where the image portion is not easy to select due to a change ofthe image, since the image is stopped, so that the image portion can beeasily selected. In addition, the desired image portion can be selectedfrom the still image by using the selection cursor.

When the manipulation of selecting the image portion by using theselection cursor is performed, the adjusting point corresponding to thegrayscale of the selected image portion is blinked, or thecharacteristic identification screen where the color tone of theadjusting point is changed is overlapped with the image signal. Theposition of the image portion in the grayscale characteristic of theentire image is distinctively represented on the graph. Accordingly, theadjusting point in the grayscale characteristic of the entire image canbe identified by using the graph before the grayscale adjusting isperformed.

In addition, when the manipulation of deciding the selected imageportion is performed, the grayscale adjusting screen at the adjustingpoint corresponding to the grayscale of the selected image portion isoverlapped with the image signal. Therefore, due to the grayscaleadjusting screen, the grayscale adjusting of the selected image portioncan be performed.

Accordingly, in the image adjusting method for the image displayapparatus according to the aspect of the invention, the desiredadjusting portion can be selected from the displayed image, and theimage adjusting for the selected adjusting portion can be performedafter the grayscale characteristic of the entire image is identified.

According to further still another aspect of the invention, there isprovided an image adjusting method for an image display apparatusincluding a display unit which displays an image represented by an imagesignal, an OSD unit which overlaps a selection cursor which is used toselect a desired image portion on the image with the image signal, amanipulator which is used to perform at least a manipulation of startingadjusting of the grayscale characteristic of the image and a selectionmanipulation of selecting the image portion by using the selectioncursor, and an image signal processing unit which stops the image andallows the OSD unit to display the selection cursor when image adjustingincluding the grayscale characteristic adjusting is performed on theimage signal and a manipulation of performing the image adjusting isperformed, the image adjusting method comprising: receiving amanipulation which is used to select the image portion in the stillimage by using the selection cursor; and blinking the selected imageportion and an image portion having a grayscale substantially equal tothat of the selected image portion in the still image.

The aforementioned image adjusting method comprises: receiving amanipulation which is used to select the image portion in the stillimage by using the selection cursor; and blinking the selected imageportion and an image portion having a grayscale substantially equal tothat of the selected image portion in the still image. Therefore, theseimage portions are displayed so as to be distinguished from other imageportions. Therefore, the selected image portion can be distinctivelyvisually perceived. In addition, even in a case where unexpected portionis selected, the portion can be identified at a glance.

Accordingly, in the image adjusting method for the image displayapparatus according to the aspect of the invention, a desired imageadjusting portion can be selected from the displayed image, so that theselected image portion can be distinctively visually perceived.

In a case where the image adjusting method for the aforementioned imagedisplay apparatus is carried out in a computer provided to the imagedisplay apparatus, the invention may be implemented with a program forexecuting the functions of the image display apparatus or acomputer-readable recording medium where the program is recorded. As arecording medium, there are a flexible disk, a CD-ROM, an opticalmagnetic disk, an IC-card, a ROM cartridge, a punch card, a printedmaterial having printed symbols such as barcodes, an internal storagedevice (RAM, ROM, or other memories) of an image display apparatus, anexternal storage device, or other computer-readable media.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a view showing a usage of a projector according to a firstembodiment of the invention.

FIG. 2 is a schematic view showing a construction of the projector.

FIG. 3A is a view an example of an input output characteristic of agrayscale point adjusting unit, and FIG. 3B is a table showing agrayscale amount per one step at each adjusting point.

FIG. 4A is a graph showing an example of a VT characteristic of a liquidcrystal light valve, and FIG. 4B is a graph showing an example of aninput output characteristic of a gamma correcting unit.

FIG. 5A is an enlarged view showing a selection cursor according to anembodiment, and FIG. 5B is a view showing an example of a selectionstatus of a image portion obtained by using the selection cursor.

FIG. 6 is a flowchart for explaining operations of a projector at a timeof performing gamma adjusting.

FIG. 7A is a view showing an example of a selection screen, and FIG. 7Bis an example of a branch screen.

FIG. 8 is a flowchart for explaining operations of customizing agrayscale characteristic in a cursor adjusting mode.

FIG. 9A is a view showing an example of a characteristic identificationscreen, and FIG. 9B is a view showing an example of a grayscaleadjusting screen.

FIG. 10A is a view showing an example of a characteristic identificationscreen, and FIG. 10B is a view showing an example of a continuationidentification screen.

FIG. 11 is a view showing an example of a manipulation screen displayedto overlap an image.

FIG. 12 is a flowchart for explaining operations of customizing agrayscale characteristic in a graph adjusting mode.

FIG. 13A is a view showing an example of a characteristic identificationscreen, FIG. 13B is a view showing an example of a grayscale adjustingscreen, and

FIG. 13C is a view showing another example of a characteristicidentification screen.

FIG. 14 is a flowchart for explaining operations of a projector at atime of performing gamma adjusting according to a second embodiment.

FIG. 15A is a view showing an example of a selection screen, and FIG.15B is an example of a branch screen.

FIG. 16 is a flowchart for explaining operations of customizing agrayscale characteristic in a cursor adjusting mode.

FIGS. 17A and 17B are views showing examples of a graph adjustingscreen, and FIG. 17C is a view showing an example of a continuationidentification screen.

FIG. 18 is a flowchart for explaining operations of customizing agrayscale characteristic in a graph adjusting mode.

FIGS. 19A and 19B are views showing examples of a graph adjustingscreen.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention are described in detail withreference to the accompanying drawings.

First Embodiment Overviews of Projector

FIG. 1 is a view showing a usage of a projector according to a firstembodiment of the invention. The projector 100 as an image displayapparatus projects an image on a screen SC based on image signalssupplied from an image signal supply unit 200 such as a personalcomputer.

In order to increase image representing performance according to imagecontents or projection configuration, the projector 100 has two imageadjusting functions and can adjust a grayscale value included in theimage signal supplied from the image signal supply unit 200. The one ofthe image adjusting functions of the projector 100 is a “gamma”adjusting function for selecting a reference γ characteristic, that is,a basic grayscale characteristic among a plurality of selection itemsstored in advance. The other is a “color mode” adjusting function forselecting a desired color mode among a plurality of selection items suchas “natural”, “dynamic”, and “theater” in order to allocate acharacteristic accent to the reference γ characteristic.

“Custom” characteristic is included in the reference γ characteristic.At a time of performing “gamma” adjusting, when the “custom”characteristic is selected, a mode proceeds. In the mode, a grayscalecharacteristic”, that is, an output grayscale value with respect to aninput grayscale value can be customized with respect to each of aplurality of specific input grayscale values (hereinafter, referred toas adjusting points). Namely, in the “custom” characteristic, thereference γ characteristic, that is, the grayscale characteristic whichis a correlation between the input and output grayscale values can becustomized.

In order to designate a to-be-customized adjusting point, the projector100 has a function of selecting a desired image portion in a projectedimage and can adjust the output grayscale value of an adjusting pointcorresponding to the grayscale value of the selected image portion.

For example, in FIG. 1, a lower left image portion of a projected imageprojected on the screen SC is selected by a selection cursor 51 forselecting an image portion. In this state, when a manipulation ofdeciding the selected image portion is performed, the projector 100 canadjust an output grayscale value of an image portion having a grayscalesubstantially equal to that of the selected image portion.

In addition to the “cursor” adjusting mode where adjusting starts fromselecting a desired image portion by using the aforementioned selectioncursor 51, the “gamma” adjusting function has a “graph” adjusting modewhere the grayscale adjusting is performed by displaying a graphrepresenting grayscale characteristics over the entire grayscale rangeand selecting a to-be-adjusted adjusting point among a plurality of theadjusting points included in the graph. In the “graph” adjusting mode,an output grayscale value corresponding to the selected adjusting pointcan be adjusted.

The selection of these functions and adjusting modes and themanipulation of the projector 100 including the adjusting manipulationare performed by a manipulator 1 disposed on a top of the projector 100mounted on a table or a remote controller 2.

The projector 100 is not limited to one mounted on a table.Alternatively, the projector 100 may be disposed on a ceiling andmanipulated by the remote controller 2.

Construction of Projector

FIG. 2 is a schematic view showing a construction of the projectoraccording to the embodiment of the invention. A schematic constructionof the projector 100 for implementing the image adjusting functions suchas “gamma” adjusting is described with reference to FIG. 2.

The projector 100 is a so-called “three-plate type liquid crystalprojector” which extracts three primary light components such as red,green, and blue light components from light radiated by a lamp 3 as alight source unit, modulating the color components by using liquidcrystal light valves 5R, 5G, and 5B as display units corresponding therespective colors light in accordance with the image signals, andmagnifying and projecting a modulated full color light (recombinedlight) by using a projection lens 7 on the screen SC. The liquid crystallight valves 5R, 5G, and 5B are optical modulation devices correspondingto red, green, and blue light and constitute an optic system 4.

The projector 100 includes the manipulator 1, the remote controller 2,the lamp 3, the optic system 4, the projection lens 7, a controller 10,a manipulation receiving unit 11, a power supply unit 12, a lamp drivingunit 13, a storage unit 14, an AD converter 15, an image signalprocessing unit 16, an image signal correcting unit 25, a liquid crystalpanel driving unit 26, and the like.

The manipulator 1 has a plurality of manipulation buttons formanipulating the projector 100. A plurality of the manipulation buttonsincludes a “Power Supply” button for starting or shutting down theprojector 100, a “Menu” button for displaying various manipulation menus(manipulation screen), a “Select” button for deciding a selectedcontent, an “Esc” button for returning to a one-screen-beforemanipulation screen, and “↑”, “↓” “→” and “←” buttons for selecting theselection items or performing one-step increment or decrement. Inaddition, “↑” and “↓” buttons are described as a set of “up” and “down”buttons, and “→” and “←” buttons are described as a set of “left” and“right” buttons. The “up” and “down” buttons and the “left” and “right”buttons functions plus and minus buttons according to types ofmanipulation screens, respectively.

The remote controller 2 is a device for manipulating the projector 100in a remote manner and includes a “γ adjusting” button for commandingthe “gamma” adjusting as well as a plurality of the manipulation buttonssame as those of the manipulator 1.

The lamp 3 may be a high pressure mercury lamp, a metal halide lamp, ahalogen lamp, or other discharging lamps capable of obtaining highluminescence.

The optic system 4 includes an integrated optic system (not shown) formodulating light radiated from the lamp 3 into light having a stabilizedluminescence distribution, an extraction optic system (not shown) forextracting primary color components of red, green, and blue from thelight having a stabilized luminescence distribution and supplying thecolor components the liquid crystal light valves 5R, 5G, and 5Bcorresponding to the colors, and a recombination optic system (notshown) for recombining the modulated color components according to theimage signals corresponding to the colors in the liquid crystal lightvalves.

The projection lens 7 magnifies the modulated full color light emittedfrom the optic system 4 and projects a full color image on the screenSC.

The controller 10 is a CPU (Central Processing Unit) and communicatessignals through a bus line Bus with other units.

When manipulation is performed by the manipulator 1 or the remotecontroller 2, the manipulation receiving unit 11 receives the associatedmanipulation and transmits manipulation signals as triggers for variousoperations to the controller 10.

The power supply unit 12 transforms, rectifies, and smoothes an AC powersupplied from an external power supply 210 in a built-in AC/DC converter(not shown) and supplies a stabilized DC voltage to units of theprojector 100.

The lamp driving unit 13 includes an igniter circuit (not shown) whichis supplied with a power from the power supply unit 12 and generates ahigh voltage to form a discharge path in order to ignite the lamp 3 anda ballast circuit which maintains a stabilized ignition state after theignition.

The storage unit 14 is constructed with, for example, flash memories,FeRAMs (Ferroelectric Random Access Memory), or other data-rewritablenon-volatile memories. The storage unit 14 stores an starting programwhich defines procedures and contents for starting the projector 100, a“grayscale characteristic adjusting program” for correcting thegrayscale values of the image signals according to preference, otherprograms for controlling the operations of the projector 100, andassociated data. The associated data include a plurality of γ correctiondata corresponding to VT characteristics representing a correlationbetween input voltage levels and transmittance of light measured withrespect to the liquid crystal light valves 5R, 5G, and 5B in aproduction stage of the projector 100.

The AC converter 15 is an AC converter including a decoder (not shown).The AD converter 15 matches various formats of analog image signals Vinsupplied from the image signal supply unit 200 with a signal type in adecoder as needed, performs AD conversion based on a sampling clockSCLK, and outputs converted digital RGB signals as image signals Din.The sampling clock SCLK is generated based on a synchronization signalSYNC included in the image signals Vin in a PLL (Phase Locked Loop)circuit of the image signal processing unit 16 and supplied to the ADconverter 15. The AD conversion of the image signals is performed inorder to perform various image signal processes with the image signalsVin.

The image signal processing unit 16 is an image process having a scalerfunction and the like and generates digital image signals Dcs byperforming various image processes such as scaling of the image signalsDin and adjusting of the grayscale values. The image signal processingunit 16 is provided with a frame memory 17 and an OSD memory 18.

The frame memory 17 is constructed with, for example, DRAMs (DynamicRandom Access Memories), and it is a three-layered memory plane whichstores image data corresponding to image signals with respect to red,green, and blue colored light.

The OSD memory 18 is an image memory which stores OSD image datarepresenting OSD images such as various manipulation screens and aselection cursor which are displayed so as to be overlapped with theprojected image.

The image signal processing unit 16 includes scaler unit 19, an OSD unit20, a grayscale point adjusting unit 21, a gamma correcting unit 22, aCPU unit 23, and the like.

The scaler unit 19 records the image data in accordance with the imagesignals Din in the frame memory 17 with respect to the RGB color signalswith resolutions of the image signals and performs a scaling process ofconverting and reading out the image data with resolutions which theliquid crystal light valves 5R, 5G, and 5B can display with andgenerating image signals matching with a resolution of a display unit.In addition, a trapezoid correction process for approximating a shape ofan effective image projected on the screen SC to a rectangular shape isperformed together with the scaling process.

The OSD unit 20 performs an OSD (On Screen Display) process foroverlapping the OSD images such as a manipulation screen on theprojected image. The OSD process is performed in a step where the imagedata corresponding to the RGB colored light is recorded in the framememory 17, and the OSD unit 20 reads out the OSD image data representingthe manipulation screen or the like from the OSD memory 18 and overlapsthe read-out OSD image data in the frame memory 17.

The grayscale point adjusting unit 21 and the gamma correcting unit 22are one-dimensional lookup tables (hereinafter, referred to as a “LUT”)disposed in an RAM area of firmware and adjusts the grayscale valuesincluded in the image signals Din. In addition, a front stage of thegrayscale point adjusting unit 21 is provided with an “RGB-YUV”converter (not shown) which converts the RGB signals into YUV signals,and a rear stage of the gamma correcting unit 22 is provided with a“YUV-RGB” converter (not shown) which converts the YUV signals into the“RGB signals. In the grayscale point adjusting unit 21 and the gammacorrecting unit 22, adjusting is performed by using the Y signal of theYUV signals.

The CPU unit 23 is a CPU which controls the image signal processing unit16 as an image processor and controls a series of the aforementionedimage processes by using the frame memory 17 and the OSD memory 18.Alternatively, the CPU unit 23 also has the functions of the controller10 such as starting of the projector 100, projecting of the image,shutting down, or whole controlling. In such a construction, thecontroller 10 may be omitted.

The image signal correcting unit 25 is a three-dimensional LUT andgenerates digital image signals by performing a color matching processfor suitably representing the image with the image signals in a colorreproducing region (GAMUT) which the liquid crystal light valves 5R, 5G,and 5B can display with respect to the image signals Dcs input from theimage signal processing unit 16 or a color irregularity correctionprocess for correcting a color irregularity unique to the liquid crystallight valves 5R, 5G, and 5B. The image signal correcting unit 25includes a DA converter (not shown) and generates analog image signalsVout by performing DA conversion on the digital image signals in the DAconverter.

The liquid crystal panel driving unit 26 supplies the image signals Voutinput from the image signal correcting unit 25 and driving voltages withrespect to the liquid crystal light valves 5R, 5G, and 5B and irradiatesthe liquid crystal light valves 5R, 5G, and 5B with the image.

Image Signal Adjusting and Correcting Methods

FIG. 3A is a graph showing an example of input output characteristics inthe LUT of the grayscale point adjusting unit 21. FIG. 4A is a graphshowing an example of a VT characteristic of a liquid crystal lightvalve, and FIG. 4B is a graph showing an example of an input outputcharacteristic of an LUT of the gamma correcting unit 22.

The image signal adjusting of the grayscale point adjusting unit 21 andthe image signal adjusting of the gamma correcting unit 22 ascharacterized portions of the embodiment of the invention are describedwith reference to FIGS. 2, 3A, 4A, and 4B.

In the projector 100, the image signal adjusting is divided into theadjusting of the grayscale point adjusting unit 21 as a first step andthe adjusting of the gamma correcting unit 22 as a second step.Therefore, the image signals Dcs output from the image signal processingunit 16 are subjected to a combination of the adjusting of the first andsecond steps.

The first step is grayscale adjusting for each adjusting point in thegrayscale point adjusting unit 21. The grayscale point adjusting unit 21performs “color mode” adjusting and “custom” characteristic adjusting in“gamma” adjusting.

An X axis of the graph shown in FIG. 3A is provided with a plurality ofadjusting points “grayscale 1 to 9” corresponding to specific inputgrayscale values. In addition, dot display portions D1 to D9representing output grayscale values at the adjusting points “grayscale1 to 9” are provided. The larger the grayscale value is, the brighterimage is represented.

The LUT of the grayscale point adjusting unit 21 having the input outputcharacteristic of graph shown in FIG. 3A outputs 10-bit output grayscalevalues in one-to-one correspondence with the 10-bit input gray values.In an initial setting of the LUT, a conversion characteristic is set to“y=x” when the X-axis input grayscale value and the Y-axis outputgrayscale value are denoted by “X” and “Y”. The setting corresponds to aγ value of 1.0 which is “natural” in terms of a color mode in the “colormode” adjusting.

The “grayscale correction data” defining the output grayscale values ofthe adjusting points “grayscale 1 to 9” are stored in the storage unit14 for each color mode, and the “grayscale correction data” of theselected color mode is set to the LUT of the grayscale point adjustingunit 21.

In addition, in the “custom” characteristic adjusting of the “gamma”adjusting, the output grayscale values of the adjusting points“grayscale 1 to 9” can be changed into desired values, and thecustomized “grayscale correction data” is set to the LUT of thegrayscale point adjusting unit 21.

In addition, although the “custom” characteristic adjusting is performedin the grayscale point adjusting unit 21, the adjusting manipulation isperformed not in a manipulation screen where a selection manipulation ofthe color mode is performed but in a manipulation screen of the “gamma”adjusting.

The second step is adjusting for correcting grayscale characteristicsunique to the liquid crystal light valves 5R, 5G, and 5B in the gammacorrecting unit 22. In the later description, the image signal adjustingof the grayscale point adjusting unit 21 is referred to as “grayscalepoint adjusting”, and the adjusting for correcting the grayscalecharacteristics unique to the liquid crystal light valves in the gammacorrecting unit 22 is referred to as “γ correction”.

In the graph shown in FIG. 4A, the vertical axis is represented in unitsof 8 bit by voltages applied to the liquid crystal light valves, and thehorizontal axis is represented by transmittance of light. As shown inFIG. 4A, the liquid crystal light valves 5R, 5G, and 5B have uniquegrayscale characteristics (referred to as voltage-to-transmittancecharacteristics, that is, VT characteristics).

The gamma correcting unit 22 performs correcting in the LUT so that thegrayscale characteristics unique to the liquid crystal light valves 5R,5G, and 5B become the input output characteristics represented as thereference 7 characteristic in the graph shown in FIG. 4A. For thereason, the LUTs provided to the liquid crystal light valves 5R, 5G, and5B of the gamma correcting unit 22 is set to “γ correction data” havingthe input output characteristic for converting the grayscalecharacteristics unique to the liquid crystal light valves 5R, 5G, and 5Bin to the reference γ characteristic (for example, a γ value of 2.2) asshown in FIG. 4B.

The projector 100 has five selection items of γ values in a range offrom 2.0 to 2.4 (0.1 interval) as the reference γ characteristic. In theproduction step for the projector 100, after the grayscalecharacteristics of the liquid crystal light valves 5R, 5G, and 5B aremeasured, the γ correction data corresponding to the reference γcharacteristic are set in advance and stored in the storage unit 14.

Since the image signal adjusting of the projector 100 includes the“grayscale point adjusting” of the grayscale point adjusting unit 21 asthe first step and the “γ correction” of the gamma correcting unit 22 asthe second step, the image signal Dcs output from the image signalprocessing unit 16 has a grayscale value obtained by combining theadjusted contents of the first and second steps. In terms of a graph,the grayscale characteristic is obtained by combining the reference γcharacteristic of the “γ correction” shown in FIG. 4A and the grayscalecharacteristic of the “grayscale point adjusting” shown in FIG. 3A.

Alternatively, the image signal adjusting may be performed in an orderof the adjusting the gamma correcting unit 22 and the adjusting of thegrayscale point adjusting unit 21.

In such a construction, various types of adjusting may be implemented byusing various combinations of a “natural”, “dynamic”, or “theater” modein the reference γ characteristic having a γ value of 2.0 and the colormodes in the reference γ characteristic having a γ value of 2.3.

Now, the “grayscale point adjusting” of the grayscale point adjustingunit 21 as the first step is described more in detail.

In the graph shown in FIG. 3A, there are nine adjusting points(grayscale 1 to 9), and six points thereof are set to the intermediategrayscale value, that is, the grayscale value 511 or less.

In addition, one point (grayscale 7) among the remaining three points isset to a substantially intermediate grayscale value such as thegrayscale value 512, so that about 78% of the adjusting points are setto be in an input grayscale range of from a low grayscale to anintermediate grayscale. According to an empirical result, more adjustingpoints are provided to a grayscale range having more adjustingfrequencies.

In order to select an adjusting point among a plurality of the adjustingpoints and adjust the output grayscale value, the “custom”characteristic among the selection items of the “gamma” adjusting isselected, and a to-be-adjusted image portion or adjusting point isdesignated in the “cursor” adjusting mode or the “graph” adjusting mode.

For example, in the “cursor” adjusting mode, when a lower left imageportion of the image projected on the screen SC shown in FIG. 1 isselected by the selection cursor 51, the adjusting point (for example,grayscale 4) closest to the grayscale value of the selected imageportion in the graph shown in FIG. 3A is selected.

The adjusting of the output grayscale value at the selected adjustingpoint is performed by using “up” and “down” buttons or “left” and“right” buttons functioning as “plus and minus” buttons in themanipulator 1 or the remote controller 2. For example, in the grayscaleadjusting screen G4 shown in FIG. 9B, the “left” and “right” buttonsfunction as the plus and minus” buttons, and in the grayscale adjustingscreen G12 shown in FIG. 17A, the “up” and “down” buttons function asthe plus and minus” buttons.

The grayscale amount per one step in the one-time increment anddecrement manipulation using the plus and minus buttons is as follows.For example, when the plus button is manipulated one time from theadjusting point “grayscale 4”, the output grayscale value is increasedby one step amount “4 counts” as a predetermined grayscale value.Similarly, when the minus button is manipulated one time, the outputgrayscale value is decreased by one step amount “4 counts”. In addition,the plus or minus button is continuously pushed, so that the outputgrayscale value is continuously increased or decreased according to acontinuously pushing time.

The adjusting grayscale amount as a predetermined grayscale amount perone step in the one-time increment and decrement manipulation at theadjusting points is defined in advance.

FIG. 3B is a table showing a grayscale amount per one step at eachadjusting point shown in FIG. 3A.

As shown in FIG. 3B, the grayscale amounts at the adjusting points areset to one step amount “2 counts” for the adjusting points “grayscale 8,9” in a high grayscale range and one step amount “4 counts” for theadjusting points in low and intermediate grayscale ranges, so that alarger adjusting amount is set to the low and intermediate grayscaleranges than the high grayscale range.

The adjusting amount are set based on the empirical result that theadjusting amount of the grayscale value in the high grayscale range issmaller than those in the low and intermediate ranges.

Details of Selection Cursor

FIG. 5A is an enlarged view showing an example of the selection cursor.FIG. 5B is a view showing an example of a selection status of an imageportion selected by using the selection cursor.

Now, the selection cursor 51 used for the “cursor” adjusting mode isdescribed in detail. FIG. 5A is an enlarged view showing the selectioncursor 51 which selects a lower left image portion in the imageprojected on the screen SC shown in FIG. 1.

The selection cursor 51 includes a pixel selection portion 52 and anannular portion 53.

The pixel selection portion 52 represents a selection region where adesired image portion is to be selected in the image and selects pixelsincluded in the selection region among effective display pixels of theliquid crystal light valves 5R, 5G, and 5B, that is, the display units.In case of the pixel selection portion 52, nine pixels P1 to P9including three consecutive pixels in each of the vertical andhorizontal directions becomes the selection region. The number of pixelsis not limited to 9, but it may be the number of pixels which includethree or more consecutive pixels in each of the vertical and horizontaldirections.

The annular portion 53 is disposed so as to surround the pixel selectionportion 52 and set to have the same color tone as that of the pixelselection portion 52. The annular portion 53 always moves together withthe pixel selection portion 52, and a positional relation therebetweenis always maintained to be constant.

Since the construction is characteristic in that the pixel selectionportion 52 is surrounded by the annular portion 53, although a size ofthe selection cursor 51 is small, a position of the selection cursor 51in the image on the screen SC shown in FIG. 1 can be distinctivelyidentified.

The selection cursor 51 is overlapped by the OSD unit 20 in a state thatthe image data for the RGB signals are recorded in the frame memory 17in the scaling process of the scaler unit 19. The position of theselection cursor 51 are identified by the CPU 23 based on the movingamount from an initial setting address in the address of the framememory 17 according to the “up” and “down” buttons and “left” and“right” buttons. The initial setting position of the selection cursor 51is a substantially central portion of the image.

The grayscale value of the pixel selected by the selection cursor 51 isobtained as luminescence signal data (Y signal data) by calculating theimage data of the selected pixel in the frame memory 17 where the imagedata for the RGB signals are recorded. More specifically, theluminescence signal data is obtained through such a calculation as“Y=0.299R+0.587G+0.144B”.

The projector 100 identifies an average value of the grayscale valuesexcluding the maximum and minimum grayscale values from the obtainedgrayscale values (Y signals) of the nine pixels as the grayscale valueof the selected image portion. The process is performed in order toremove extraneous pixel components caused from noises in the image.Alternatively, an average value of the grayscale values of all theselected pixels may be identified as the grayscale value of the selectedimage portion.

FIG. 5B shows another example of the selection cursor which selectsedges of an image V. When the position of the selection cursor 51reaches the edge of the image V, the CPU unit 23 controls the entireportions of the pixel selection portion 52 not to protrude from theimage V. In the figure, the image V is shown to be a bright image havingall the grayscale values close to a white color.

The selection cursors 51 i and 51 j select the lower left portions ofthe image V. For the convenience of description, the selection cursors51 i and 51 j are displayed to be disposed on the same screen. However,in an actual case, only the one of the selection cursors is displayed.

The pixel selection portion 52 of the selection cursor 51 i selects ninepixels in the lowest end of the lower left portion of the image V. Insuch a construction, the annular portion 53 is displayed on only theinner portion of the image V.

Similarly, the selection cursor 51 j which selects the pixels in thelower left portion of the image V is displayed on only the inner portionof the image V.

In such a construction, even in a case where the edge of the image V isselected by the selection cursor, since a shape of the annular potion 53is displayed within the image V, the selection cursor can bedistinctively identified.

Both of the selection cursors 51 i and 51 j which are displayed on thebright image V close to a white color have a black tone. On the otherhand, in the image on the screen SC shown in FIG. 1, the selectioncursor 51 has a white color.

The color tone of the selection cursor is controlled by the CPU unit 23so that the color tone becomes one of white and black tones and thecontrast to the selected image portion becomes larger according to thegrayscale of the selected image portion.

Procedures of First Image Adjusting Process 1

FIG. 6 is a flowchart for explaining operations of the projector 100 ata time of performing the “gamma” adjusting. FIG. 7A is a view showing anexample of the selection screen, and FIG. 7B is a view showing anexample of a branch screen.

Now, the operations according to the first embodiment at the time ofperforming the “gamma” adjusting are described with reference to mainlyFIG. 6 and additionally FIGS. 7A, 7B, and 2.

The projector 100 is constructed with such a configuration as shown inFIG. 1 and manipulated by the remote controller 2.

In Step S1, the controller 10 determines whether or not there is amanipulation for performing the “gamma” adjusting according to amanipulation signal from the manipulation receiving unit 11. When thereis the manipulation for performing the “gamma” adjusting, the processproceeds to Step S2. Where there is not manipulation, the manipulationis waited for. The “grayscale adjusting program” of the storage unit 14is started by the manipulation, and the following processes areperformed according toe the procedures and contents of the grayscaleadjusting defined in the program.

In Step S2, the controller 10 allows the image signal processing unit 16to overlap the selection screen G1 shown in FIG. 7A with the imagesignal.

Five γ values of from 2.0 to 2.4 as selection items of the grayscalecharacteristic and “custom” and “reset” as seven selection items of thecustom characteristic are displayed on the selection screen G1. A graphrepresenting the selected grayscale characteristics is displayed on theright side of the selection items. The selection screen G1 shows a statethat the “custom” is selected, and a graph at the right side of thescreen shows the grayscale characteristics.

The graph of the selection screen G1 shows the grayscale characteristicsobtained by combining the “γ correction” and the adjustingcharacteristics of the “grayscale point adjusting”. However, thestraight line denotes the reference γ characteristic having a γ value of2.2. In the initial setting of the projector 100, since the reference γcharacteristic has a γ value of 2.2, the scale axis of the graph is setto be represented by a straight line when the γ value is 2.2. In theinitial setting of the custom characteristic, the reference γcharacteristic is also set to have a γ value of 2.2.

In addition, in various manipulation screens described later, graphsthereof may be set the same scale axis.

Under the selection screen G1, the manipulation button namescorresponding to the manipulator 1 or the remote controller 2 formanipulating the selection screen G1 are displayed. More specifically,“Esc button” for returning the manipulation step to one-step-beforemanipulation step, “Up Down button” for selecting the grayscalecharacteristic, “Select button” for deciding the selected grayscalecharacteristic, and “Menu button” for ending the adjusting aredisplayed. In the other manipulation screens described later, suchmanipulation guiding display has the same meaning.

In the later description, when a new manipulation screen is displayed,the previously displayed manipulation screens are closed. In addition,after the manipulation screen is displayed, if any manipulation is notperformed for a predetermined time interval, for example, two minutes,the manipulation screen, and the adjusting is treated to end.

In Step S3, the controller 10 determines whether or not there is aselection manipulation of selecting one characteristic from theselection items of the grayscale characteristics on the selection screenG1 based on the manipulation signal from the manipulation receiving unit11. When there is a selection manipulation, the process proceeds to StepS4. When there is no selection manipulation, the manipulation is waitedfor.

In Step S4, the controller 10 sets the γ correction data of the selectedgrayscale characteristic to the LUT of the gamma correcting unit 22 andproject the image adjusted according to the grayscale characteristic. Inthe step, the image projected on a background of the selection screen G1becomes the image adjusted according to the selected grayscalecharacteristic.

In Step S5, the controller 10 determines whether or not there is adecision manipulation of deciding the selected grayscale characteristicbased on the manipulation signal from the manipulation receiving unit11. When there is the decision manipulation, the process proceeds toStep S6. When there is no decision manipulation, the process returns toStep S3, so that the selection manipulation is received unit thedecision manipulation is performed.

In Step S6, the controller 10 determines whether or not the decidedgrayscale characteristic is the “custom” characteristic. When there isthe “custom” characteristic, the process proceeds to Step S7. When thereis no “custom” characteristic, the process proceeds to Step S10. Inaddition, when there is the “custom” characteristic, the operations offrom an operation of proceeding to a process for changing the grayscalecharacteristic, that is, a correlation between the input grayscale valueand the output grayscale value to an manipulation of selecting anddeciding the “custom” characteristic correspond to a startingmanipulation for starting changing the correlation.

In Step S7, the controller 10 allows the image signal processing unit 16to overlap the branch screen G2 shown in FIG. 7B with the image signal.

A selection items for selecting one of the “cursor” adjusting moderepresented by “adjust based on an image” and “graph” adjusting moderepresented by “adjust based on a graph” is displayed on the branchscreen G2. The branch screen G2 shows a state that the “cursor”adjusting mode is selected.

In Step S8, the controller 10 determines whether or not there is aselection decision manipulation of selecting and deciding the “cursor”adjusting mode based on the manipulation signal from the manipulationreceiving unit 11. When there is the selection decision manipulation,the process proceeds to a subroutine of “cursor” adjusting mode. Whenthere is no selection decision manipulation, the process proceeds toStep S9.

In Step S9, the controller 10 determines whether or not there is aselection decision manipulation of selecting and deciding the “graph”adjusting mode based on the manipulation signal from the manipulationreceiving unit 11. When there is the selection decision manipulation,the process proceeds to a subroutine of the “graph” adjusting mode. Whenthere is not selection decision manipulation, the process returns toStep S7 and waits for the selection and decision manipulations.

Next, a case where the decided grayscale characteristic is not the“custom” characteristic in Step 6 is described.

In Step S10, the controller 10 allows the image signal processing unit16 to close the selection screen G1 in a state the γ correction data ofthe selected and decided grayscale characteristic is set to the LUT ofthe gamma correcting unit 22, so that the “gamma” adjusting ends.

In addition, the record that the cursor” adjusting mode or the “graph”adjusting mode is selected and decided is stored in the storage unit 14,and at the time of the next manipulation, in Step S7, the branch screenis displayed in a state that the stored adjusting mode is selected.

In addition, when the selected grayscale characteristic is the “custom”characteristic, Step S6 is not limited to displaying of the branchscreen G2. Alternatively, it may be a process routine of directlyperforming one of “graph” and “cursor” adjusting modes.

Procedures of First Image Adjusting Process 2: Cursor Adjusting Mode

FIG. 8 is a flowchart for explaining operations at a time of customizingthe grayscale characteristic in the “cursor” adjusting mode. FIG. 9A isa view showing an example of a characteristic identification screen, andFIG. 9B is a view showing an example of a grayscale adjusting screen.FIG. 10A is a view showing an example of the characteristicidentification screen, and FIG. 10B is a view showing an example of acontinuation identification screen.

Now, the operations at the time of customizing the grayscalecharacteristic in the “cursor” adjusting mode are described withreference to mainly FIG. 8 and additionally FIGS. 9A, 9B, 10A, 10B, and2.

In Step S21, the controller 10 allows the image signal processing unit16 to stop the image. This is because a moving image is not easy toselect an image portion thereof.

In Step S22, the controller 10 allows the image signal processing unit16 to overlap the “selection cursor” with the image signal. The state isthe same as that of the selection cursor 51 on the image in the screenSC shown in FIG. 1.

In Step S23, the controller 10 determines whether or not there is animage selection manipulation of selecting a predetermined image portionby the “selection cursor” based on the manipulation signal from themanipulation receiving unit 11. When there is the image selectionmanipulation, the process proceeds to Step S24. When there is no imageselection manipulation, the image selection manipulation is waited for.

In Step S24, the controller 10 allows the image signal processing unit16 to blink the selected image portion and an image portion having agrayscale substantially equal to that of the selected image portion andoverlap the characteristic identification screen G3 shown in FIG. 9Awith the image signal.

In the process, firstly, the controller 10 reads out the image data forthe RGB colors of the selected image portion selected by the “selectioncursor” from the frame memory 17 and obtains the luminescence signaldata (Y signal data) from the image data of the pixels. Next, thecontroller obtains an average value of the Y signal data excluding themaximum and minimum grayscale values from the Y signal data of thepixels. Next, the adjusting point closet to the obtained Y signal datais selected as the to-be-adjusted adjusting point.

In addition, the blinking of the image portion is performed by changingthe output grayscale value of the selected adjusting point in the“grayscale correction date” of the grayscale point adjusting unit 21(LUT) in a period of 1 Hz at plus 32 counts and minus 32 counts of theinitial output grayscale value.

In addition, on the characteristic identification screen G3, a statethat the adjusting point “grayscale 2” is selected is displayed, and adot displayed portion D2 of the adjusting point “grayscale 2” is blinkedin synchronization with the blinking cycle of the image portion. Themethod of displaying the dot displayed portion is not limited to theblinking thereof. Alternatively, a method of changing the color tone ofthe dot displayed portion into other color tones such as orangedifferent from those of the other dot displayed portions may be used.

In Step S25, the controller 10 determines whether or not there is animage decision manipulation of deciding the selected image portion, thatis, the selected adjusting point based on the manipulation signal fromthe manipulation receiving unit 11. When there is the image decisionmanipulation, the process proceeds to Step S26. When there is no imagedecision manipulation, the image decision manipulation is waited for.

In Step S26, the controller 10 allows the image signal processing unit16 to stop blinking of the image portion and overlap the grayscaleadjusting screen G4 shown in FIG. 9B with the image signal. In addition,Step S24 may be a process routine of displaying the grayscale adjustingscreen G4 instead of the characteristic identification screen G3. Insuch a procedure, the determination of the image decision manipulationin Step S25 is not needed, and the blinking of the image portion isstopped by using the adjusting manipulation to the grayscale adjustingscreen G4 as a trigger.

In Step S27, the controller 10 determines whether or not there is amanipulation of adjusting the output grayscale value based on themanipulation signal from the manipulation receiving unit 11. When thereis the adjusting manipulation, the process proceeds to Step S28. Whenthere is no adjusting manipulation, the adjusting manipulation is waitedfor.

In step S28, the controller 10 sequentially corrects the “grayscalecorrection data” according to the adjusting manipulation, sets thecorrected “grayscale correction data” to the LUT of the grayscale pointadjusting unit 21, and performs the adjusting of the image signal basedon the grayscale characteristic. In this step, the image projected on abackground of the grayscale adjusting screen G4 becomes the imageadjusted in real-time according to the grayscale characteristiccorresponding to the adjusted contents.

In Step S29, the controller 10 determines whether or not there is amanipulation of deciding the adjusted contents based on the manipulationsignal from the manipulation receiving unit 11. When there is thedecision manipulation, the process proceeds to Step S30. When there isno decision manipulation, the process returns to Step S27 and receivesthe adjusting manipulation until there is the decision manipulation.

In Step S30, the controller 10 allows the image signal processing unit16 to overlap the characteristic identification screen G5 shown in FIG.10A with the image signal. On the characteristic identification screenG5, a graph representing the grayscale characteristic subjected to thegrayscale point adjusting is displayed.

In Step S31, the controller 10 determines whether or not there is amanipulation of deciding the adjusting result based on the manipulationsignal from the manipulation receiving unit 11. When there is thedecision manipulation, the process proceeds to Step S32. When there isno decision manipulation, the decision manipulation is waited for. Whenthere is the decision manipulation, the adjusted contents are stored asthe “grayscale correction data” of the “custom” characteristic in thestorage unit 14. In addition, a manipulation screen for naming thepreviously adjusted “custom” characteristics is displayed. For example,there may be provided a process routine for naming the characteristics,for example, “custom 1”, “custom B” and storing the characteristics.

In Step S32, the controller 10 allows the image signal processing unit16 to overlap the continuation identification screen G6 shown in FIG.10B with the image signal. On the continuation identification screen G6,an identification indicator for determining whether or not the adjustingof the “cursor” adjusting mode is continued is displayed.

In Step S33, the controller 10 determines whether or not there is amanipulation of continuing the adjusting based on the manipulationsignal from the manipulation receiving unit 11. When there is thecontinuation manipulation, the process returns to Step S22 and continuesthe adjusting of the “cursor” adjusting mode by using the previouslyadjusted “grayscale correction data” as base data. When there is nocontinuation manipulation, the continuation identification screen G6 isclosed, so that the adjusting of the “cursor” adjusting mode ends.

FIG. 11 is a view showing an example of the manipulation screendisplayed so as to overlap the image. Now, the displayed positions ofthe characteristic identification screen and the grayscale adjustingscreen are described.

In Step S24, the characteristic identification screen G3 shown in FIG.9A is overlapped with the image signal by using the image signalmanipulation as a trigger. However, with respect to the displayedposition of the characteristic identification screen G3, thecharacteristic identification screen G3 is displayed at a lower rightportion of the screen as shown in FIG. 11. This is because the imagesignal processing unit 16 controls the characteristic identificationscreen G3 not to be overlapped with the image portion selected by theselection cursor 51. For the convenience of description, in FIG. 11, theselection cursor 51 together with the characteristic identificationscreen G3 are displayed on the same screen. However, as described above,in an actual case, both are not displayed on the same screen.

In addition, the displayed positions in the initial setting of themanipulation screens such as the branch screen G2, the characteristicidentification screens G3, G5, G7, and G9, the grayscale adjustingscreens G4 and G8 are set at the lower left portion of the image.However, the displayed positions on the characteristic identificationscreens G3, G5, G7, and G9 and the grayscale adjusting screens G4 and G8are controlled so as not to be overlapped with the selected imageportion or the image portion corresponding to the selected adjustingpoint. In addition, the sizes of the manipulation screens are set to be¼ or less of the image area like the characteristic identificationscreen G3.

Now, the reasons that, in Step S24, the blinking of the image portion isperformed by increment and decrement of ±32 counts of the outputgrayscale value and the blinking period is set to be 1 Hz are described.

An output grayscale value of a general image display apparatus isdisplayed with 8 to 10 bits, so that 256 to 1024 output grayscale valuesare generated. When a portion of the screen is visualized by theblinking of the image portion, if the blinking level is periodicallyincreased and decreased from the “zero” level to “maximum” levelaccording to the full scale of the output grayscale level, since thecontrast is too high, the image is flickered, so that observer's eyesbecome fatigued. In addition, since the response of the display unitcannot be caught up with, an inharmonious image may be formed. In orderto prevent this phenomenon, the blinking of the selected image portionis preferably performed with a grayscale amount of ±10% or less of thefull scale of the output grayscale value.

Therefore, although the increment and decrement amounts of the outputgrayscale value are set to be ±32 counts, the amounts are not limitedthereto. Alternatively, the grayscale amount of ±10% or less of the fullscale of the output grayscale value may be used.

The reason that the blinking period is set to 1 Hz is that, with respectto the visual characteristic of a human, it is known that, if theblinking period exceeds 3 Hz, unpleasant feeling caused from theflickering of the image is increased. Therefore, the blinking period isnot limited to 1 Hz, but it may be in a range of from 0.5 Hz to 3 Hz.

Procedures of Image Adjusting Process 3: Graph Adjusting Mode

FIG. 12 is a flowchart for explaining operations at a time ofcustomizing the grayscale characteristic in the “graph” adjusting mode.FIGS. 13A and 13C are view showing an example of a characteristicidentification screen, and FIG. 13B is a view showing an example of agrayscale adjusting screen.

Now, the operations at the time of customizing the grayscalecharacteristic in the “graph” adjusting mode are described withreference to mainly FIG. 12 and additionally FIGS. 13A, 13B, 13C, and 2.

In Step S41, the controller 10 allows the image signal processing unit16 to stop the image.

In Step S42, the controller 10 allows the image signal processing unit16 to overlap the characteristic identification screen G7 shown in FIG.13A with the image signal. On the characteristic identification screenG7, the adjusting point “grayscale 1” is displayed in a selected state,and the image portion corresponding to the adjusting point “grayscale 1”is blinked in a period of 1 Hz. In the dot displayed portion D1 havingthe adjusting point “grayscale 1” is synchronously blinked.

With respect to the method of displaying the dot displayed portion, amethod of changing the color tone of the dot displayed portion intoother color tones such as orange different from those of the other dotdisplayed portions may be used.

In Step S43, the controller 10 determines whether or not there is amanipulation of selecting the adjusting point based on the manipulationsignal from the manipulation receiving unit 11. When there is theselection manipulation, the process proceeds to Step S44. When there isno selection manipulation, the selection manipulation is waited for.

In Step S44, the controller 10 allows the image signal processing unit16 to blink the image portion corresponding to the selected adjustingportion in a period of 1 Hz. In addition, the dot displayed portion ofthe selected adjusting point on the characteristic identification screenG7 is also synchronously blinked. In addition, the blinking of the imageportion is performed by changing the output grayscale value of theselected adjusting point in the “grayscale correction date” of thegrayscale point adjusting unit 21 (LUT) in a period of 1 Hz at plus 32counts and minus 32 counts of the initial output grayscale value.

In Step S45, the controller 10 determines whether or not there is amanipulation of deciding the selected adjusting point based on themanipulation signal from the manipulation receiving unit 11. When thereis the decision manipulation, the process proceeds to Step S46. Whenthere is no decision manipulation, the process returns to Step S43 andreceives the selection manipulation unit the decision manipulation isperformed.

In Step S46, the controller 10 allows the image signal processing unit16 to stop the blinking of the image portion and overlap the grayscaleadjusting screen G8 shown in FIG. 13B with the image signal.Alternatively, Step S44 may be a process routine of closing thecharacteristic identification screen G7 and displaying the grayscaleadjusting screen G8. In such a procedure, the determination of theselection decision manipulation in Step S45 is not needed, and theblinking of the image portion is stopped by using the adjustingmanipulation to the grayscale adjusting screen G8 as a trigger.

In Step S47, the controller 10 determines whether or not there is amanipulation of adjusting the output grayscale value based on themanipulation signal from the manipulation receiving unit 11. Where thereis the adjusting manipulation, the process proceeds to Step S48. Whenthere is no adjusting manipulation, the adjusting manipulation is waitedfor.

In step S48, the controller 10 sequentially corrects the “grayscalecorrection data” according to the adjusting manipulation, sets thecorrected “grayscale correction data” to the LUT of the grayscale pointadjusting unit 21, and performs the adjusting of the image signal basedon the grayscale characteristic. In such a construction, the projectedimage adjusted according to the corrected grayscale characteristic isdisplayed on a background of the grayscale adjusting screen G8.

In Step S49, the controller 10 determines whether or not there is amanipulation of deciding the adjusted contents based on the manipulationsignal from the manipulation receiving unit 11. When there is thedecision manipulation, the process returns to Step S42. When there is nodecision manipulation, the process returns to Step S47 and receives theadjusting manipulation until the decision manipulation is performed.

In addition, when there is the decision manipulation, the manipulationscreen displayed in Step S42 becomes the characteristic identificationscreen G9 shown in FIG. 13C. In the characteristic identification screenG9, the output grayscale value of, for example, the adjusting point“grayscale 5” is the grayscale value including the previously performedadjusted contents. In addition, the adjusted contents are stored as the“grayscale correction data” of the “custom” characteristic in thestorage unit 14 in advance. In addition, a manipulation screen fornaming the previously adjusted “custom” characteristics is displayed.For example, there may be provided a process routine for naming thecharacteristics, for example, “custom 1”, “custom B” and storing thecharacteristics.

In the embodiment, the OSD unit 20 which overlaps the branch screen G2,the characteristic identification screens G3, G7, and G9, the grayscaleadjusting screens G4 and G8, and the selection cursor 51 on theprojected image after the “custom” characteristic is selected among aplurality of the grayscale characteristics displayed on the selectionscreen G1, the manipulator 1 which receives the manipulations accordingto the screens, and the controller 10 which controls the OSD unit 20 andthe manipulator 1 and corrects the “grayscale correction data” accordingto the manipulation contents of the manipulator 1 correspond to thegrayscale characteristic changing unit according to the embodiment ofthe invention.

According to the aforementioned embodiment, the following advantages canbe obtained.

(1) The storage unit 14 stores a plurality of the grayscalecharacteristics including the custom characteristic which can customizethe characteristic used for the image adjusting. Therefore, since thereare a large number of the selection items of the grayscalecharacteristic, the projector 100 can cope with the selection itemscorresponding to the user's various preferences.

When the grayscale characteristic of the selection screen G1 isperformed, the image signal processing unit 16 adjusts the image signalaccording to the selected grayscale characteristic, so that the image isprojected according the adjusted image signal. Therefore, the imageincluding the adjusted contents on the background of the selectionscreen G1 can be identified in the step of selecting the adjustedcontents, that is, the step before the adjusted contents are decided.

Therefore, in the projector 100, since the image adjusting can beperformed according to the user's preferences, the image including theadjusted contents can be identified in the step of selecting theadjusted contents.

(2) The graph representing a correlation between the input and outputgrayscale levels of the selected grayscale characteristics is includedin the selection screen G1. Therefore, the graph representing theselected grayscale characteristic can be visually perceived.

Accordingly, in the projector 100, in addition to the image includingthe adjusted contents, the graph representing the grayscalecharacteristic can be identified in the step of selecting the adjustedcontents.

(3) In the OSD unit 20, the branch screen G2 which is used to select oneof the graph adjusting mode and the cursor adjusting mode by usingselecting and deciding the custom characteristic as a trigger isoverlapped with the image signal. Therefore, due to the branch screenG2, one of the graph adjusting mode and the cursor adjusting mode can beselected.

Accordingly, in the projector 100, the adjusting method can be selectedaccording to the user's preferences.

(4) The record that the cursor” adjusting mode or the “graph” adjustingmode is selected and decided is stored in the storage unit 14, and atthe time of the next manipulation, the branch screen G2 is displayed ina state that the adjusting mode for the selected record is selected.Therefore, a probability that the user performs the selectionmanipulation for the adjusting mode is reduced.

Accordingly, the projector 100 can be conveniently used.

(5) When the custom characteristic is selected, in any adjusting mode ofthe “cursor” adjusting mode and the “graph” adjusting mode, thecharacteristic identification screen, that is, a graph smaller than theimage representing the grayscale characteristic in the initial settingof the custom characteristic is displayed. Therefore, due to thecharacteristic identification screen, the grayscale characteristic inthe initial setting of the custom characteristic can be identified.

In addition, in the graph” adjusting mode, when a manipulation ofselecting one among a plurality of the dot displayed portionsrepresenting the output grayscale levels for the adjusting points in thegraph on the characteristic identification screen G7 is performed, theOSD unit 20 stops the overlapping of the characteristic identificationscreen G7 and overlaps the grayscale adjusting screen G8 smaller thanthe still image of which output grayscale level of the selectedadjusting point is to be adjusted with the image signal. Therefore, dueto the grayscale adjusting screen G8, the adjusting of the outputgrayscale level of the selected adjusting point can be performed.

Accordingly, in the projector 100, after the grayscale characteristic isidentified by using the graph, the image adjusting can be performedaccording to the user's preferences.

(6) When the “cursor” adjusting mode is selected and decided, theselection cursor 51 is displayed, and the image is stopped. Therefore,although the moving image is not easy to select, the selection of theimage portion by using the selection cursor 51 can be easily performedon the still image.

In addition, when the manipulation of selecting the image portion isperformed by using the selection cursor 51, after the decisionmanipulation of the selected image portion is performed, the OSD unit 20overlaps the grayscale adjusting screen G4 smaller than the still imageof which output grayscale level at the adjusting points corresponding tothe selected image portion is to be adjusted with the image signal.Therefore, due to the grayscale adjusting screen G4, the adjusting ofthe output grayscale level at the selected adjusting point can beperformed.

Accordingly, in the projector 100, since a desired image portion can beeasily selected, the image adjusting can be performed according to theuser's preferences.

(7) When the adjusting manipulation of the grayscale levels on thegrayscale adjusting screens G4 and G8 is performed, the image signalprocessing unit 16 sequentially adjusts the grayscale value of the imageportion corresponding to the adjusting point of the still imageaccording to the output grayscale level which is subjected to theadjusting manipulation. Therefore, the image including the adjustedcontents can be identified in real-time in the step of performing theadjusting.

Accordingly, in the projector 100, the image adjusting can be performedaccording to the user's preferences, and the image including theadjusted contents can be identified in real-time in the step ofperforming the adjusting.

(8) A plurality of the adjusting points of the custom characteristic aredistributed so that a larger number of the adjusting points aredistributed to a range of from the low grayscale value to theintermediate grayscale value at the input side. Therefore, in theprojector 100, a large number of the adjusting points are provided tothe grayscale range needed to improve the “image quality” which the userhighly expects in the grayscale adjusting.

In addition, predetermined output grayscale amounts for the adjustingpoints are set so that a larger amount is provided to the adjustingpoints in the low grayscale range than the adjusting points in the highgrayscale range. The adjusting amounts per one step in the graphadjusting screen and the grayscale adjusting screens G4 and G8 are setto the adjusting amounts satisfying the needed usage.

Accordingly, the projector 100 can be easily used, so that the imageadjusting can be performed according to the user's preferences.

(9) The sizes of the manipulation screens including the selection screenG1, the characteristic identification screens G3, G5, G7, and G9, thegrayscale adjusting screens G4 and G8, and the branch screen G2 are setto be ¼ or less of the image. Therefore, although the area covered bythe manipulation screen is excluded, the image having ¾ or more of theentire area can be identified. In addition, the manipulation screen isdisposed in an inner side of one of four corners of the image having asubstantially rectangular shape as the initial setting. Therefore, thecentral portion of the image cannot be covered by the manipulationscreen.

In addition, the OSD unit moves the position of the manipulation screenin an inner region of the image so that the selected image portioncannot be overlapped with the manipulation screen. Therefore, theadjusting state of the selected image portion which needs to be mostcarefully adjusted can be identified at the time of the adjusting.

Accordingly, in the projector 100, the image adjusting can be performedwhile the image state is always identified.

(10) The grayscale characteristic in the default initial setting of thecustom characteristic can be changed and is set to one grayscalecharacteristic among a plurality of the grayscale characteristics storedin the storage unit 14. Therefore, the grayscale characteristicaccording to the user's preferences can be selected as a referencecharacteristic.

In addition, the adjusted custom characteristic is stored in the storageunit 14, and when the selection screen G1 is displayed at the time ofthe next manipulation, the adjusted custom characteristic is displayedas one of the selection items of a plurality of the grayscalecharacteristics. Therefore, the adjusted custom characteristics arestored, so that it can be easily reproduced.

Accordingly, the projector 100 can be easily used, so that the imageadjusting can be performed according to the user's preferences.

(11) In the “cursor” adjusting mode, when the manipulation for the imageadjusting is performed, the image signal processing unit 16 stops theimage and displays the selection cursor 51 for selecting the desiredimage portion on the image. Even in case of a moving image where theimage portion is not easy to selection due to a change of the image,since the image is stopped, so that the image portion can be easilyselected. In addition, the desired image portion can be selected fromthe still image by using the selection cursor 51.

When the manipulation of selecting the image portion by using theselection cursor 51 is performed, the OSD unit 20 blinks the adjustingpoint corresponding to the selected image portion or overlap thecharacteristic identification screen G3 where the color tone of theadjusting point is changed with the image signal. Therefore, thegrayscales of the image portions over the entire grayscale range aredistinctively represented on the graph. Accordingly, the to-be-adjustedadjusting point can be identified by using the graph before thegrayscale adjusting is performed.

In addition, when the manipulation of deciding the selected imageportion is performed, the OSD unit 20 overlaps the grayscale adjustingscreen G4 at the adjusting point corresponding to the grayscale of theselected image portion with the image signal. Therefore, due to thegrayscale adjusting screen G4, the grayscale adjusting of the selectedimage portion can be performed.

Accordingly, in the projector 100, the desired adjusting portion can beselected from the projected image, and the image adjusting for theselected adjusting portion can be performed after the grayscalecharacteristic is identified.

(12) The image signal processing unit 16 includes a gamma correctingunit 22 which corrects one reference γ characteristic among a pluralityof the reference γ characteristics defined in advance in order to matchthe grayscale characteristics unique to the liquid crystal light valves5R, 5G, and 5B with the visual characteristics of a human and agrayscale point adjusting unit 21 which adjusts the output grayscalevalues for a plurality of the adjusting points disposed according to theinput levels of the reference γ characteristic. The functions areperformed by individual dedicated units. Therefore, since the dedicatedconstructions can be formed, it is possible to simplify theconstructions.

In addition, the grayscale adjusting to the image signal in the imagesignal processing unit 16 is performed by using the grayscalecharacteristic obtained by combining the γ correction in the gammacorrecting unit 22 and the grayscale point adjusting in the grayscalepoint adjusting unit 21. Therefore, due to the two adjusting portions, ahighly-accurate grayscale adjusting can be performed.

When the adjusting of the output grayscale value in each of thegrayscale adjusting screens G4 and G8 of the selected adjusting point isperformed, the grayscale point adjusting unit 21 changes the outputgrayscale value of the adjusting point according to the adjustedcontents. Therefore, the image on the background of each of thegrayscale adjusting screens G4 and G8 can be updated by an imageincluding the adjusted contents in real-time.

Accordingly, in the projector 100, since the highly-accurate grayscaleadjusting can be performed by using a simple grayscale adjustingconstruction, the image including the adjusted contents can beidentified in real-time.

(13) In the “cursor” adjusting mode, the selection cursor 51 includesthe pixel selection portion 52 which has a size capable of selecting aplurality of the three or more consecutive pixels in the liquid crystallight valves. Therefore, the selected portion according to the user'sintention can be determined based on the pixel data in a plurality ofthe pixels having a width.

In addition, with respect to the adjusting point corresponding to theselected image portion, the adjusting point having the input grayscalelevel closest to the average value of the grayscale values for aplurality of the pixels selected by the pixel selection portion or theaverage value excluding the maximum and minimum grayscale values fromthe grayscale values for a plurality of the pixels selected by the pixelselection portion is selected. Therefore, since the influence of thepixel data including the noise can be reduced, the adjusting pointcorresponding to the image portion according to the user's intention canbe selected.

Accordingly, in the projector 100, the adjusting portion according tothe user's intention can be accurately selected from the projectedimage.

(14) In the “cursor” adjusting mode, the pixel selection portion 52 hasa size capable of selecting, preferably, a total of nine pixels in asquare shape where the three consecutive pixels are arrayed in each ofthe vertical and horizontal directions. Therefore, although the averagevalue is obtained from the grayscale values excluding the pixels havingthe maximum and minimum grayscale values, the effective pixel data forthe seven pixels can be obtained. In addition, since the pixel selectionportion has a suitable size over the entire image, it can be easilyvisually perceived. In addition, since the pixel selection portion has asquare shape, the image portion can be easily selected.

Accordingly, in the projector 100, the adjusting portion according tothe user's intention can be easily and accurately selected from theprojected image.

(15) In the “cursor” adjusting mode, the selection cursor 51 furtherincludes the annular portion 53 which is disposed along thecircumference of the pixel selection portion 52 to have a shape which isone-step larger than an outer portion of the pixel selection portion 52.In addition, a relative position of the annular portion 53 to the pixelselection portion 52 is always maintained constant, and the annularpotion together with the pixel selection portion 52 is moved on thestill image. Therefore, the selection cursor 51 has a specific shapehaving the annular portion 53 of which size is larger by one step thanthat of the pixel selection portion 52, and a large selection cursor canbe distinctively displayed on the image.

In addition, the image signal processing unit 16 adjusts the color toneof the selection cursor 51 based on a color tone having high contrastamong a color tone of the image portion selected by the selection cursor51 and a color tone of one of black and white. Therefore, the color toneof the selection cursor 51 can be easily visually perceived.

Accordingly, due to the distinctively displayed selection cursor 51, adesired image portion can be easily selected.

Accordingly, in the projector 100, since the selection cursor isdistinctively displayed on the image, the desired image portion can beeasily selected.

(16) In the “cursor” adjusting mode, when the selection manipulation ofthe image portion is performed by using the selection cursor 51, theposition of the pixel selection portion 52 is controlled by the imagesignal processing unit 16 so that the entire portions of the pixelselection portion 52 are not protruded from the still image, and whenthe pixel selection portion 52 reaches the edge of the still image, theselection cursor 51 is displayed in a state that a portion of the imagecorresponding to the annular portion 53 protruding from the still imageis excluded. Therefore, due to the selection cursor 51, the imageportion in the edge of the image can be selected from the image, andalthough the edge of the image is selected, the selection cursor 51 canbe visually perceived.

Accordingly, in the projector 100, due to the selection cursor, thedesired image portion can be selected from all the effective imageregions.

(17) In the “cursor” adjusting mode, the image signal processing unit 16stops the image and displays the selection cursor 51 for selecting thedesired image portion on the display unit. Even in case of a movingimage where the image portion is not easy to selection due to a changeof the image, since the image is stopped, so that the image portion canbe easily selected. In addition, the desired image portion can beselected from the still image by using the selection cursor 51.

In addition, when the image portion is selected from the still image bythe selection cursor 51, the image signal processing unit 16 blinks theselected image portion of the still image and the image portion having agrayscale substantially equal to that of the selected image portion.Therefore, these image portions are displayed so as to be distinguishedfrom other image portions. Therefore, the selected image portion can bedistinctively visually perceived. In addition, even in a case whereunexpected portion is selected, the portion can be identified at aglance.

Accordingly, in the projector 100, the desired image grayscale portioncan be selected from the displayed image, and the selected image portioncan be distinctively visually perceived.

(18) In the “cursor” adjusting mode, the blinking of the image portionselected by the selection cursor 51 and the image portion having agrayscale substantially equal to that of the selected image portion isperformed by periodically increasing and decreasing the output grayscalevalue at the adjusting point having the input grayscale level closest tothe grayscale value of the selected image portion among a plurality ofthe adjusting points corresponding to the input grayscale level of theimage signal representing the still image. Therefore, the selected imageportion and the image portion having a grayscale substantially equal tothat of the selected image portion can be blinked by using such a simplemethod of increasing and decreasing the output grayscale value at theone adjusting point.

Accordingly, in the projector 100, the selected image portion and theimage portion selected together with the selected image portion can bevisually perceived and identified by using such a simple method.

(19) The image signal processing unit 16 includes a gamma correctingunit 22 which corrects one reference grayscale characteristic among aplurality of the reference grayscale characteristics defined in advancein order to match the grayscale characteristics unique to the displayunit with the visual characteristic of a human and a grayscale pointadjusting unit 21 which adjusts the output grayscale value for aplurality of the adjusting points disposed according to the input levelsin the reference grayscale characteristic, and each of the gammacorrection unit and the grayscale point adjusting unit is constructedwith one-dimensional LUT. Each of the gamma correction unit and thegrayscale point adjusting unit has a simple construction havingdedicated functions. Accordingly, the correction data set to each of theLUTs may be constructed to be not large complex data but simple data.

In addition, the blinking of the image portion selected by the selectioncursor 51 and the image portion having a grayscale substantially equalto that of the selected image portion is performed by the grayscalepoint adjusting unit 21. Therefore, the image portion can be blinkedwithout influence to the reference grayscale characteristic.

Accordingly, in the projector 100, the selected image portion and theimage portion selected together with the selected image portion can bevisually perceived and identified by using such a simple construction.

(20) The increment and decrement amounts of the output grayscale valuesused to blink the image portion at the adjusting point corresponding tothe selected image portion selected by the selection cursor 51 in the“cursor” adjusting mode or at the selected adjusting point in the“graph” adjusting mode are set to be ±10% or less of the full scale ofthe output grayscale value of the grayscale characteristic. Therefore,due to such a suitable contrast, the image portion can be visuallyperceived without the fatigue of the observer's eyes. In addition, theresponse of the display unit can be sufficiently caught up with.

In addition, the blinking period of the image portion is set to be in arange of from 0.5 Hz to 3 Hz or less. Therefore, unpleasant feelingcaused from the flicker can be prevented, and the image portion can bedistinctively visually perceived.

Accordingly, in the projector 100, the selected image portion can bedistinctively visually perceived without unpleasant feeling.

(21) In the “cursor” adjusting mode, the blinking period of the imageportion selected by the selection cursor 51 or the blinking period ofthe image portion corresponding to the selected adjusting portion in the“graph” adjusting mode is in synchronization with the blinking period ofthe dot displayed portions of the characteristic identification screensG3 and G7.

Therefore, it can be visually perceived that the selected image portionand the dot displayed portion at the adjusting points corresponding tothe characteristic identification screens G3 and G7 are equal to eachother. In addition, the periods are synchronized with each other, sothat the visually unpleasant feeling can be prevented.

In the image display apparatus according to the embodiment of theinvention, it can be visually represented that the selected imageportion corresponds to the dot displayed portion.

Second Embodiment Procedures of Second Image Adjusting Process 1: Up toBranch Screen

FIG. 14 is a flowchart for explaining operations of the projector 100 ata time of performing the “gamma” adjusting. FIG. 15A is a view showingan example of the selection screen, and FIG. 15B is a view showing anexample of the branch screen.

Now, the operations of the process up to the branch screen according tothe second embodiment in the image adjusting performed by the projector100 according to the first embodiment are described with reference tomainly FIG. 14 and additionally FIGS. 15A, 15B, and 2. The same elementsas those of the first embodiment are denoted by the same referencenumerals, and redundant description is omitted.

The procedures and the manipulation screens in the process of the imageadjusting according to the second embodiment are different from those ofthe process of the image adjusting according to the first embodiment.Therefore, the “grayscale adjusting program” for defining the proceduresand contents of the image adjusting according to the second embodimenthas functions different from those of the program according to the firstembodiment. In addition, some of the manipulation screens stored in theOSD memory 18 are different from the manipulation screens according tothe first embodiment. In addition, the reference γ characteristic in the“custom” characteristic is set to have a γ value of 2.4 by themanipulation of the manipulator 1 in advance.

The projector 100 is constructed with such a configuration as shown inFIG. 1 and manipulated by the manipulator 1.

In Step S51, the controller 10 determines whether or not there is amanipulation for performing the “gamma” adjusting according to amanipulation signal from the manipulation receiving unit 11. When thereis the manipulation for performing the “gamma” adjusting, the processproceeds to Step S52. Where there is not manipulation, the manipulationis waited for. The “grayscale adjusting program” of the storage unit 14is started by the manipulation, and the following processes areperformed according toe the procedures and contents of the grayscalecharacteristic defined in the program.

In Step S52, the controller 10 allows the image signal processing unit16 to overlap the selection screen G10 shown in FIG. 15A with the imagesignal.

The selection screen G10 is the same as the selection screen G1 shown inFIG. 7A. On the selection screen G10, a state that the “custom”characteristic is selected is displayed, but the graph is a curved lineunlike the graph displayed on the selection screen G1. This is becausethe reference γ characteristic in the “custom” characteristic is set tohave a γ value of 2.4, and the γ value of 2.4 is represented on thescale of the graph having the γ value of 2.2 as a reference straightcharacteristic.

In Step S53, the controller 10 determines whether or not there is aselection manipulation of selecting one characteristic from theselection items of the grayscale characteristics on the selection screenG10 based on the manipulation signal from the manipulation receivingunit 11. When there is a selection manipulation, the process proceeds toStep S54. When there is no selection manipulation, the manipulation iswaited for.

In Step S54, the controller 10 allows the image signal processing unit16 to update the selection screen G10 according to the adjustedcontents. The updated contents of the selection screen S10 includesselecting and displayed the indication (for example, 2.3) representingthe selected grayscale characteristic at the lower left side of thescreen. In this step, the grayscale adjusting of the background image isnot performed.

In Step S55, the controller 10 determines whether or not there is adecision manipulation of deciding the selected grayscale characteristicbased on the manipulation signal from the manipulation receiving unit11. When there is the decision manipulation, the process proceeds toStep S56. When there is no decision manipulation, the process returns toStep S53, so that the selection manipulation is received unit thedecision manipulation is performed.

In Step S56, the controller 10 determines whether or not the decidedgrayscale characteristic is the “custom” characteristic. When there isthe “custom” characteristic, the process proceeds to Step S58. Whenthere is no “custom” characteristic, the process proceeds to Step S57.In addition, when there is the “custom” characteristic, the operationsof from an operation of proceeding to a process for changing thegrayscale characteristic, that is, a correlation between the inputgrayscale value and the output grayscale value to an manipulation ofselecting and deciding the “custom” characteristic correspond to astarting manipulation for starting changing the correlation.

In Step S57, the controller 10 sets the γ correction data of theselected grayscale characteristic to the LUT of the gamma correctingunit 22 and project the image adjusted according to the grayscalecharacteristic. Next, the process returns to Step S53, so that amanipulation of selecting the grayscale characteristic is waited foragain. In the step, the image projected on a background of the selectionscreen G10 becomes the image adjusted according to the selectedgrayscale characteristic, and the graph representing the selectedgrayscale characteristic is displayed on the selection screen G10. Inorder to end the adjusting, the “Menu” button of the manipulator 1 orthe remote controller 2 is pushed according to the display in the lowerportion of the selection screen G10.

Next, a case of the “custom” characteristic in Step S56 is described.

In Step S58, the controller 10 allows the image signal processing unit16 to overlap the branch screen G11 shown in FIG. 15B with the imagesignal. The branch screen G11 is the same as the branch screen G2 shownin FIG. 7B. On the branch screen G11, the graph adjusting mode isselected.

In Step S59, the controller 10 determines whether or not there is aselection decision manipulation of selecting and deciding the “cursor”adjusting mode based on the manipulation signal from the manipulationreceiving unit 11. When there is the selection decision manipulation,the process proceeds to a subroutine of “cursor” adjusting mode. Whenthere is no selection decision manipulation, the process proceeds toStep S60.

In Step S60, the controller 10 determines whether or not there is aselection decision manipulation of selecting and deciding the “graph”adjusting mode based on the manipulation signal from the manipulationreceiving unit 11. When there is the selection decision manipulation,the process proceeds to a subroutine of the “graph” adjusting mode. Whenthere is not selection decision manipulation, the process returns toStep S58 and waits for the selection and decision manipulations.

Procedures of Second Image Adjusting Process 2: Cursor Adjusting Mode

FIG. 16 is a flowchart for explaining operations at a time ofcustomizing the grayscale characteristic in the “cursor” adjusting mode.FIGS. 17A and 17B are views showing an example of the graph adjustingscreen, and FIG. 17C is a view showing an example of a continuationidentification screen.

Now, the operations in the “cursor” adjusting mode of the imageadjusting of the projector 100 according to the second embodiment aredescribed with reference to mainly FIG. 16 and additionally FIGS. 17A,17B, 17C, and 2.

In Step S71, the controller 10 allows the image signal processing unit16 to stop the image. This is because a moving image is not easy toselect an image portion thereof.

In Step S72, the controller 10 allows the image signal processing unit16 to overlap the “selection cursor” with the image signal. This stateis the same as that of the selection cursor 51 on image in the screen SCshown in FIG. 1.

In Step S73, the controller 10 determines whether or not there is animage selection manipulation of selecting a predetermined image portionby the “selection cursor” based on the manipulation signal from themanipulation receiving unit 11. When there is the image selectionmanipulation, the process proceeds to Step S74. When there is no imageselection manipulation, the image selection manipulation is waited for.

In Step S74, the controller 10 allows the image signal processing unit16 to blink the selected image portion and an image portion having agrayscale substantially equal to that of the selected image portion andoverlap the graph adjusting screen G12 shown in FIG. 17A with the imagesignal.

In the process, firstly, the controller 10 reads out the image data forthe RGB colors of the selected image portion selected by the “selectioncursor” from the frame memory 17 and obtains the luminescence signaldata (Y signal data) from the image data of the pixels. Next, thecontroller obtains an average value of the Y signal data excluding themaximum and minimum grayscale values from the Y signal data of thepixels. Next, the adjusting point closet to the obtained Y signal datais selected as the to-be-adjusted adjusting point.

In addition, the blinking of the image portion is performed by changingthe output grayscale value of the selected adjusting point in the“grayscale correction date” of the grayscale point adjusting unit 21(LUT) in a period of 1 Hz at plus 32 counts and minus 32 counts of theinitial output grayscale value.

In addition, on the graph adjusting screen G12, a state that theadjusting point “grayscale 3” is selected is displayed, and a dotdisplayed portion D3 of the adjusting point “grayscale 3” has such acolor tone as orange different from the color tone (white) of other dotdisplayed portions. Alternatively, a method of displaying the dotdisplayed portion may be an inverted blinking of the dot displayedpotion in synchronization with the blinking of the image portion.

On the graph adjusting screen G12, a text, “the orange colored portionis a to-be-adjusted object. Please adjust the grayscale.” is displayedto urge the adjusting, and an indicator 55 for identifying the adjustingstate of the adjusting point corresponding to the selected image portionis additionally disposed. The indicator 55 enlarges the displayedadjusting state involved with the moving-up and moving-down of the dotdisplayed portion of the selected adjusting point according to theadjusting.

In addition, the position and size of the graph adjusting screen G12displayed on the image are the same as those of the characteristicidentification screen G3 shown in FIG. 11 and controlled so as not tooverlap the image portion selected by the selection cursor 51 by theimage signal processing unit 16.

In step S75, the controller 10 determines whether or not there is amanipulation of adjusting the output grayscale value based on themanipulation signal from the manipulation receiving unit 11. When thereis the adjusting manipulation, the process proceeds to Step S76. Whenthere is no adjusting manipulation, the adjusting manipulation is waitedfor.

In Step S76, the controller 10 allows the image signal processing unit16 to stop the blinking of the image portion, sequentially corrects the“grayscale correction data” according to the adjusting manipulation,sets the corrected “grayscale correction data” to the LUT of thegrayscale point adjusting unit 21, and performs the adjusting of theimage signal based on the grayscale characteristic. In addition, thegraph adjusting screen is updated, and as shown in the graph adjustingscreen G13 of FIG. 17B, the graph representing the adjusted contents isdisplayed, so that a text, “please check the adjusting result” isdisplayed. In this step, the image projected on a background of thegrayscale adjusting screen G13 becomes the image adjusted in real-timeaccording to the grayscale characteristic corresponding to the adjustedcontents.

In Step S77, the controller 10 determines whether or not there is amanipulation of deciding the adjusted contents based on the manipulationsignal from the manipulation receiving unit 11. When there is thedecision manipulation, the process proceeds to Step S78. When there isno decision manipulation, the process returns to Step S75 and receivesthe adjusting manipulation until there is the decision manipulation.

In addition, when there is the decision manipulation, the adjustedcontents are stored as the “grayscale correction data” of the “custom”characteristic in the storage unit 14.

In Step S78, the controller 10 allows the image signal processing unit16 to overlap the continuation identification screen G14 shown in FIG.17C with the image signal. On the continuation identification screenG14, an identification indicator for determining whether or not theadjusting of the “cursor” adjusting mode is continued is displayed.

In Step S79, the controller 10 determines whether or not there is amanipulation of continuing the adjusting based on the manipulationsignal from the manipulation receiving unit 11. When there is thecontinuation manipulation, the process returns to Step S72 and continuesthe adjusting of the “cursor” adjusting mode by using the previouslyadjusted “grayscale correction data” as base data. When there is nocontinuation manipulation, the continuation identification screen G14 isclosed, so that the adjusting of the “cursor” adjusting mode ends.

Procedures of Image Adjusting Process 3: Graph Adjusting Mode

FIG. 18 is a flowchart for explaining operations at a time ofcustomizing the grayscale characteristic in the “graph” adjusting mode.FIGS. 19A and 19B are views showing an example of the graph adjustingscreen.

Now, the operations at the time of customizing the grayscalecharacteristic in the “graph” adjusting mode are described withreference to mainly FIG. 18 and additionally FIGS. 19A, 19B, and 2.

In Step S81, the controller 10 allows the image signal processing unit16 to stop the image. This is because a moving image is not easy toselect an image portion thereof.

In Step S82, the controller 10 allows the image signal processing unit16 to overlap the graph adjusting screen G15 shown in FIG. 19A with theimage signal. On the graph adjusting screen G15, the adjusting point“grayscale 1” is displayed in a selected state, and the image portioncorresponding to the adjusting point “grayscale 1” is blinked in aperiod of 1 Hz. In addition, a dot displayed portion D1 of the adjustingpoint “grayscale 1” has such a color tone as orange different from thecolor tone (white) of other dot displayed portions.

On the graph adjusting screen G15, a manipulation guidance text isdisplayed, and an indicator 55 for identifying the adjusting situationof the selected adjusting point is additionally provided.

In Step S83, the controller 10 determines whether or not there is amanipulation of selecting the adjusting points based on the manipulationsignal from the manipulation receiving unit 11. When there is theselection manipulation, the process proceeds to Step S84. When there isno selection manipulation, the selection manipulation is waited for.

In Step S84, the controller 10 allows the image signal processing unit16 to blink the image portion corresponding to the selected adjustingportion in a period of 1 Hz. In the graph adjusting screen, the colortone of the dot displayed portion of the selected adjusting point ischarged into orange. In addition, the blinking of the image portion isperformed by changing the output grayscale value of the selectedadjusting point in the “grayscale correction date” of the grayscalepoint adjusting unit 21 (LUT) in a period of 1 Hz at plus 32 counts andminus 32 counts of the initial output grayscale value.

In step 85, the controller 10 determines whether or not there is amanipulation of adjusting the output grayscale value based on themanipulation signal from the manipulation receiving unit 11. When thereis the adjusting manipulation, the process proceeds to Step S86. Whenthere is no adjusting manipulation, the adjusting manipulation is waitedfor.

In step S86, the controller 10 sequentially corrects the “grayscalecorrection data” according to the adjusting manipulation, sets thecorrected “grayscale correction data” to the LUT of the grayscale pointadjusting unit 21, and performs the correction of the image signal basedon the grayscale characteristic. Next, the graph adjusting screen isupdated again, and the graph representing the adjusted contents isdisplayed. In this step, the image projected on a background of thegraph adjusting screen becomes the image adjusted in real-time accordingto the grayscale characteristic corresponding to the adjusted contents.

In Step S87, the controller 10 determines whether or not there is amanipulation of deciding the adjusted contents based on the manipulationsignal from the manipulation receiving unit 11. When there is thedecision manipulation, the graph adjusting screen G16 is closed, so thatthe adjusting ends. When there is no decision manipulation, the processreturns to Step S83 and receives the selection and adjustingmanipulations until the decision manipulation is performed.

The graph adjusting screen G16 shown in FIG. 19B represents a state thata plurality of the selection and adjusting manipulation are performed.Since the output grayscale values of adjusting points “grayscale 2 to 7”are adjusted by using a plurality of the adjusting, the customizedgrayscale characteristic becomes different from the grayscalecharacteristic as a base of the graph adjusting screen G15.

In the embodiment, the OSD unit 20 which overlaps the branch screen G11,the graph adjusting screens G12, G13, G15, and G16, and the selectioncursor 51 on the projected image after the “custom” characteristic isselected among a plurality of the grayscale characteristics displayed onthe selection screen G10, the manipulator 1 which receives themanipulations according to the screens, and the controller 10 whichcontrols the OSD unit 20 and the manipulator 1 and corrects the“grayscale correction data” according to the manipulation contents ofthe manipulator 1 correspond to the grayscale characteristic changingunit according to the embodiment of the invention.

According to the aforementioned invention, the following advantages aswell as the advantages of the first embodiment can be obtained.

(1) When the custom characteristic is selected, in any adjusting mode ofthe “cursor” adjusting mode and the “graph” adjusting mode, the graphadjusting screens G12 and G15 including the graph representing theinitial setting of the custom characteristic are displayed, and thegraph adjusting screens G12 and G15 represent the output grayscalelevels at a plurality of the adjusting points disposed according to theinput grayscale levels and have a plurality of the dot displayedportions for adjusting the grayscale characteristic. Therefore, due tothe graph adjusting screens G12 and G15, the grayscale characteristiccan be adjusted while the grayscale characteristic in the initialsetting of the custom characteristic is identified.

Accordingly, in the projector 100, the image adjusting can be performedaccording to the user's preferences while the grayscale characteristicis identified by using the graph.

(2) The image signal processing unit 16 blinks the image portioncorresponding to the selected adjusting point in a period of 1 Hz andchanges the color tone of the dot displayed portion at the selectedadjusting point on the graph adjusting screens G12 and G15 into orange.Therefore, it can be visually perceived that the blinking image portioncorresponds to the orange colored grayscale point in the grayscalecharacteristic.

Accordingly, in the projector 100, it can be visually represented thatthe selected image portion corresponds to the dot displayed portion.

(3) When the adjusting manipulation of the grayscale levels on the graphadjusting screens G12 and G15 is performed, the image signal processingunit 16 sequentially adjusts the grayscale value of the image portioncorresponding to the adjusting portion of the still image according tothe output grayscale level which is subjected to the adjustingmanipulation. The image including the adjusted contents can be visuallyidentified in the step of performing the adjusting.

In addition, due to the graphs of the graph adjusting screens G12 andG15 and the indicator 55, the adjusting state of the grayscalecharacteristic can be identified in real-time.

Accordingly, in the projector 100, the image including the adjustingstate and the adjusted state of the grayscale characteristic can beidentified in real-time in the step of performing the adjusting.

(4) The manipulation screens displayed in the “graph” adjusting mode areonly the graph adjusting screens G15 and G16, and all the adjustingmanipulations can be implemented by using one type of the manipulationscreen. Therefore, the manipulation can be effectively performed.

In addition, after the adjusting for one adjusting point is completed,the decision manipulation, the continuation identification manipulation,or the like is not needed, so that the adjusting at the other adjustingpoints can be continuously performed. Therefore, the adjustingefficiency can be improved. In addition, since the adjusted grayscalecharacteristic can be visually perceived in real-time by using the graphand the image, the adjusting state can be easily identified.

Accordingly, the projector 100 can be conveniently used, and the imageadjusting can be performed according to the user's preferences.

The invention is not limited to the aforementioned embodiments, butvarious modification and changes of the aforementioned embodiments areavailable. Hereinafter, modified examples of the invention aredescribed.

Modified Example 1

Modified Example 1 is described with reference to FIG. 2. In theaforementioned embodiments, the selection of the image portion or theadjusting of the output grayscale value in the cursor selection mode isperformed by using the “up” and “down” buttons or the “left” and “right”buttons of the manipulator 1 or the remote controller 2. However, theinvention is not limited thereto. For example, a track ball as apointing device is provided to the remote controller 2, and a devicedriver corresponding to the track ball is stored in the storage unit 14.By manipulating the track ball, the selection of the image portion orthe adjusting operation for the output grayscale value may be performed.

In such a construction of the projector 100, the adjusting manipulationcan be efficiently performed.

Modified Example 2

Modified Example 2 is described with reference to FIG. 2. In theaforementioned embodiments and the modified example, the “grayscalepoint adjusting” and the “γ correction” is performed by using the Ysignal among the YUV signals. However, the invention is not limitedthereto.

For example, a luminescence table which is used to apply luminescencedate for each of the color signals based on the pixel data for RGBsignals is provided in the storage unit 14, and the “grayscale pointadjusting” and the “γ correction” may be performed by using theluminescence data for the RGB signals.

In such a construction, advantages same as those of the aforementionedembodiments and modified example can be obtained.

Modified Example 3

Modified Example 3 is described with reference to FIG. 2. In theaforementioned embodiments and the modified examples, the projector 100is exemplified as a three-plate type liquid crystal projector usingthree plates of the liquid crystal light valves 5R, 5G, and 5B asoptical modulation devices. The invention is not limited thereto.

For example, the projector may be a single-plate type liquid crystallight valve which is constructed by regularly disposing red, green, andblue color filters in a lattice shape and extracting modulated lighthaving a full color with a single plate. In addition, the projector maybe constructed with a reflective liquid crystal display apparatus or atilt mirror device. In addition, the projector may be a rear typeprojector having such an optical modulation device and the screen.

In such a construction, advantages same as those of the aforementionedembodiments and modified example can be obtained.

Modified Example 4

Modified Example 4 is described with reference to FIG. 2. In theaforementioned embodiments and the modified examples, the image displayapparatus is exemplified as the projector. The invention is not limitedthereto. Any image display apparatus for displaying an image displayedaccording to input image signals on a display unit may be used.

For example, CRT displays, liquid crystal displays, plasma displays,organic EL displays, field emission displays or the like may be used,and advantages same as those of the aforementioned embodiments andmodified example can be obtained.

1. An image display apparatus comprising: an image signal processingunit which adjusts an input grayscale values included in an input imagesignal according to a predetermined grayscale characteristic; a displayunit which displays an image based on an image signal included in anoutput grayscale value adjusted by the image signal processing unit; anda grayscale characteristic changing unit which changes a correlationbetween the input and output grayscale values defined based on thegrayscale characteristic.